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Options

This page describes every control in the Xbar-R Chart dialog, in the order the tabs appear, followed by the Analysis Pane that opens once the chart exists. What each option means statistically is on the Math Details page.

The Dialog

Above the tabs, a Chart: row of three radio buttons decides which panels are drawn: Xbar-R (both, selected by default), Xbar only, and R only. The ribbon entries Xbar and R open this same dialog with the matching radio already selected, and the dialog title stays Xbar-R Chart in all three cases. The choice only decides what is drawn: both panels are computed either way, and the worksheet is named after the variant rather than after the dialog, so Xbar only produces a sheet named Xbar Chart and R only one named Range Chart.

The tabs

The dialog is a set of tabs with one set of buttons underneath. Data is always first and always the tab the dialog opens on.

Tab	What it holds
Data	What is charted: the data source, the data types, the columns, and how rows are collected into points
Limits & Estimation	How the center line and the control limits are worked out: the sigma method, the limit type and multiplier, historical values, the baseline, any transformation, and the phase splits
Rules & Display	The out-of-control tests and what is drawn on the chart
Capability	Specification limits and the capability summary. Present only on the charts whose page says so

Switching tabs never recalculates anything, so you can move between them freely and read your settings back. Only a change you make triggers the rebuild.

Xbar-R has all four tabs, including Capability.

Data Tab

Selecting the data

Choosing any control chart from the ribbon opens the Data Selection window before the chart dialog appears. It is the same window for every chart.

Control	Type	Default	What it does
Selected Range:	Text box	The block Quantum XL expands around the current selection	The cells the analysis reads. It keeps tracking the Excel selection while the window is open, so you can select on the sheet instead of typing.
Shrink and expand button	Button, tooltip "Shrink/Expand form"	Expanded	Collapses everything below the range box so you can see the sheet. It expands again on its own when you change the Excel selection.
Data in Columns	Radio button	Selected when the range has at least as many rows as columns, or when the range is inside an Excel Table	Each selected column becomes one column of data.
Data in Rows	Radio button	Selected when the range has more columns than rows and is not inside an Excel Table	Each selected row becomes one column of data. The block is transposed before the dialog opens.
One Group Data	Radio button	Not selected	Treats the whole rectangular block as a single column of data, named by the Dataset Name box. Available on every control chart.
First Row/Column is Header	Check box	Checked when the range is inside an Excel Table with Data in Columns, or when the first cell holds text; unchecked otherwise	Uses the first row (or first column, in Data in Rows) as the column names. Header text is cleaned of line breaks and tabs, trimmed, and truncated to 50 characters.
Exclude Data in Hidden Cells	Check box	Checked	Drops hidden rows and hidden columns before the data reaches the analysis. Cells you have marked as outliers stay attached to the right values.
Dataset Name:	Text box	Dataset	Names the single column of data in One Group Data mode. Maximum 30 characters, and the characters : \ / ? * [ ] are not allowed. Left blank it reverts to Dataset.
Help	Button		Opens the Data Selection help page, and falls back to the copy installed with Quantum XL if no internet connection is available.
Cancel	Button		Closes the window. The analysis never starts.
Next >	Button		Validates the selection and opens the chart dialog.

Two of these controls appear only in certain states:

• Dataset Name: is visible only when One Group Data is selected.
• First Row/Column is Header is hidden entirely when One Group Data is selected, because that mode ignores headers.

An illustration beside the orientation radios changes to match the orientation you pick. Nothing is validated while you type: the checks below all run when you press Next >.

What Data Selection checks

Pressing Next > runs these checks in order. Any failure returns you to the window with your entries still in place.

Condition	Message
No range entered	"Please select a range of cells for the analysis."
Header row hidden while First Row/Column is Header and Exclude Data in Hidden Cells are both on	"Cannot omit hidden rows when first row contains headers. The header row is hidden."
Header column hidden, same combination, in Data in Rows	"Cannot omit hidden columns when first column contains headers. The header column is hidden."
The range contains merged cells	"The selection contains merged cells at {address}. Please unmerge cells before continuing."
Nothing selected at all	"(Data in Columns) You must select 1 or more columns for this analysis." or "(Data in Rows) You must select 1 or more rows for this analysis."
Several separate areas selected, unequal heights (Data in Columns)	"(Data in Columns) All non-contiguous areas must have the same number of rows."
Several separate areas selected, different starting rows (Data in Columns)	"(Data in Columns) All non-contiguous areas must start at the same row."
Several separate areas selected, unequal widths (Data in Rows)	"(Data in Rows) All non-contiguous areas must have the same number of columns."
Several separate areas selected, different starting columns (Data in Rows)	"(Data in Rows) All non-contiguous areas must start at the same column."
Two selected areas overlap	"Non-contiguous areas cannot overlap."
Illegal character in Dataset Name:	"The characters :\/?*[] cannot be used as the name of a dataset."
Dataset Name: longer than 30 characters	"The maximum length of the dataset name is 30 characters, the current length is N characters."

The two dataset-name checks apply only in One Group Data mode, the only mode in which that box is used. Merged cells are the one condition worth checking before you start: the analysis cannot read them at all, and unmerging is the only remedy.

If your range touches an Excel Table

Three Yes / No / Cancel prompts can appear after you press Next >. Two of them change a setting you made on the form, so read the answer you give as an instruction to Quantum XL, not just as an acknowledgement.

Prompt title	Message	Yes	No	Cancel
Mixed Table Selection	"Your selection includes both an Excel Table and non-table region, would you like to include both?"	Continues with both regions included	Returns you to the Data Selection window so you can narrow the range	Ends the analysis
Table Orientation	"Typically, when analyzing data in a table the data orientation is in Columns. Are you sure you want to analyze this in rows?"	Continues in Data in Rows as you set it	Changes the orientation to Data in Columns for you and returns you to the window	Ends the analysis
Table Headers	"The Excel table has headers, would you like to use them as the headers for your data?"	Checks First Row/Column is Header for you and continues	Continues with the box as you left it	Ends the analysis

So answering No to the orientation prompt, or Yes to the headers prompt, rewrites the choice showing on the form. If the column names or the orientation in the chart dialog are not what you expected, one of these two answers is the usual reason.

How the Data Selection choices shape the Data tab

The chart dialog never re-asks these questions, so what you chose in the Data Selection window decides what the Data tab shows.

Data Selection choice	What you see on the Data tab
First Row/Column is Header checked	Every list shows your own header text, cleaned and truncated to 50 characters
First Row/Column is Header unchecked	Every list shows generated names: Col A, Col B, and so on in Data in Columns, or Row 1, Row 2, and so on in Data in Rows
Header checked but one header cell is blank	That one column falls back to its generated name; the others keep your text
Exclude Data in Hidden Cells checked	Row counts in the metadata line are the counts after the hidden cells are dropped, and a column that was entirely hidden does not appear in any list at all
Data in Rows	Each selected row is offered as a column, named from the first cell of that row
One Group Data	A single column, named by the Dataset Name box

To change any of them, use Back at the bottom of the chart dialog rather than cancelling: it returns you to the Data Selection window with your range still filled in.

The Data tab

The Data tab is always the first tab, and it is where you choose what is charted. It holds, from the top:

• The Excel and GroupBy radio buttons, which decide how the rows are divided.
• A red message line that appears when a selection cannot be honored. The text clears itself after about five seconds, so read it when it appears.
• The Data Types list, one row per column.
• The column slot lists, which differ by chart family: what is measured or counted, the optional X-axis labels, and any extra role the chart needs.
• The GroupBy region, visible only in GroupBy mode.
• A metadata line at the bottom describing the column you last clicked.

Every slot list is a small scrolling box of check boxes. Three behaviors are the same in all of them:

• A long column name is shortened with an ellipsis; hover it to see the full name.
• A column that is not available is disabled, not hidden, so you can see that it exists and that something else is using it or that its data type does not fit.
• A disabled check box does not say why it is disabled. The usual reason is that the column is already doing another job on this chart.

The type drop-downs inside these lists ignore the mouse wheel and let the list scroll instead, so scrolling past a drop-down cannot silently change a data type.

On Xbar-R the slot lists are Measurement Columns, X-Axis Labels (Optional), and the Subgroups group with its subgroup identifier drop-down.

Excel or GroupBy

Option	Default	What it produces
Excel	Selected	The rows are used in sheet order. Each column you check produces its own chart.
GroupBy		The rows are divided by the value of one or more grouping columns, and the same checked columns are charted once per group, so the number of charts is multiplied by the number of groups.

The GroupBy region is shown only while GroupBy is selected.

Switching back to Excel discards your GroupBy selection. The grouping columns are cleared, not remembered, so returning to GroupBy means building the list again. Nothing warns you before this happens.

Choosing GroupBy and leaving the order list empty is not caught on the Data tab. It fails when the chart is built, with "GroupBy mode selected but no GroupBy columns specified."

Data Types

The Data Types list shows every column with a drop-down holding the type Quantum XL guessed from its cells. Changing a type here changes it for the whole analysis. The drop-down always offers the same five choices, in this order:

Type	Use it for
Continuous	Measurements that can take any decimal value
Nominal	Text categories
DateTime	Cells holding a real Excel date and time
Count	Whole numbers that cannot be negative, such as counts of defects or units
Integer	Whole numbers, negative values allowed

Changing a type has three effects worth knowing before you use it:

• If the new type is one the chart cannot measure, the column is disabled in the slot list and, if it was checked, it is unchecked for you.
• If the new type is one the chart can measure, the column becomes available again.
• The Invalid count on the metadata line is counted against the type currently chosen, so the same column reports a different Invalid count under a different type.

A type change also triggers the preview cycle described under the footer buttons, so the worksheets are rewritten for the new type immediately.

Date/Time columns that hold no dates

Setting a column to DateTime when its cells are not real dates stops the analysis with one of two messages. Each names the fix.

• Times with no calendar date: "Column '{0}' is set to Date/Time, but its values are times of day with no calendar date. Excel only provides a true date/time when the cell includes a date. Add a date to these cells, for example, enter 1/1/2026 2:30 PM instead of 2:30 PM, then run the analysis again."
• Plain numbers: "Column '{0}' is set to Date/Time, but its values are plain numbers, not dates. Change this column's data type to Continuous (or Count / Integer), then run the analysis again."

Quantum XL chooses between the two by looking at the cell format and the values, so the message you get tells you which of the two problems you actually have.

Measurement Columns

Check the columns holding the measured values. This is the only required selection on the Data tab.

• Accepted types: Continuous, Integer and Count. A Nominal or DateTime column is offered but disabled.
• The first available column is checked for you when the dialog opens. Everything else starts cleared.
• More than one column can be checked. On charts with no Subgroups group each checked column produces its own chart. On charts that have one, the subgroup mode decides whether a second checked column is a second chart or a second observation inside every subgroup.
• Retyping a checked column to a type the chart cannot measure unchecks it for you.
• A checked column is not available as the X-axis label, the split column, the subgroup ID, the part column, or a grouping column.

With nothing checked, the chart cannot be built. Pressing Finish in that state stops the analysis with a message naming the missing selection and reopens the dialog with your settings intact.

Subgroups

The Subgroups group decides how rows are collected into the points on the chart. It is three radio buttons, and the choice you make changes what the check boxes in the measurement list mean. Read this table before you check a second column.

Mode	How a subgroup is formed	Charts produced	What a second checked column means	Columns required
Constant size:	Consecutive rows, n at a time, within each column	One chart per checked column	Another, separate chart	1
Subgroup ID column:	Rows that share the same value in the ID column	One chart per checked column, all using the same ID column	Another, separate chart	1
Subgroups across columns	Each row is one subgroup, and the checked columns are the observations inside it	Exactly one chart	Another observation inside every subgroup, not another chart	2

Constant size: is selected by default.

Details attached to each mode:

• Constant size: shows the n = box beside it. Rows are taken in sheet order, and the number of points is the row count divided by n, discarding the remainder: a trailing group of fewer than n rows is not charted at all. With 52 rows and n set to 5 the chart has 10 points and the last two rows are unused. If a partly filled last subgroup matters, adjust the range instead. An X-axis label, if you chose one, is read from the first row of each subgroup.
• Subgroup ID column: shows a drop-down beside it. Any data type is accepted, because the values are compared as the text they display. Leaving the mode releases the column and sets the drop-down back to empty, so returning to this mode means choosing the column again.
• Subgroups across columns needs at least two checked columns. Choosing it with fewer raises "Subgroups across columns needs at least 2 selected measurement columns." in the red line. The message appears only at the moment you click the radio button: if you uncheck columns down to one afterwards, no message appears and Finish simply stops working. Its tooltip reads "Each row is one subgroup; every selected measurement column is a measurement within it."

The chart does not redraw while a mode is incomplete. Choosing Subgroup ID column: before picking a column, or Subgroups across columns with only one column checked, deliberately leaves the preview alone until the choice can be honored.

Two consequences are specific to Xbar-R:

• Subgroup ID column: and Subgroups across columns can both produce subgroups of unequal size, because an identifier can repeat a different number of times and a row can have blanks in some of the checked columns. Unequal sizes are supported: the limits then step from point to point instead of running straight.
• A subgroup left with only one usable value still plots a mean on the Xbar panel, but it has no range, so the Range panel shows a gap at that position.

Subgroup size

The n = box beside Constant size: sets how many consecutive rows make one subgroup. Its tooltip reads "Number of consecutive observations per subgroup".

• Type: whole number. Default: 2.
• It is visible only while Constant size: is selected.
• It is read when you leave the box, not as you type.
• The lowest value it accepts depends on the chart, and a value below that floor snaps back to the floor with no message at all:

Chart	Lowest n	Why
Xbar-R, Xbar-S, I-MR-R/S	2	A subgroup of one has no range and no standard deviation, so these charts cannot be built from it
EWMA, CUSUM	1	Both are legitimate charts of individual values

• There is no upper limit and no check against how many rows you actually have. A value larger than your data passes the dialog and fails when the chart is built.
• Non-numeric text is rejected by reverting the box when you leave it, again with no message.

If a value you typed is not the one showing after you click elsewhere, it was below the floor for this chart.

On Xbar-R the floor is 2. A subgroup of one has no range, so there would be nothing to draw on the lower panel.

X-Axis Labels (Optional)

Check one column here to label the points along the horizontal axis. Any data type is accepted: dates, text, or numbers.

• Nothing is checked by default, and leaving it empty is normal. The points are then numbered.
• The list is drawn as check boxes but behaves as a single choice: checking a second column silently unchecks the first.
• The choice only relabels the axis. It never changes what is plotted, how subgroups are formed, or how the limits are estimated.
• A column used as the X-axis label is not available for any other job on the chart.

One column, one job

A column can hold only one role on the chart, and up to six roles compete for it:

Role	Where you choose it	Present on
The measured column	Measurement Columns, Data tab	every variable chart
X-axis label	X-Axis Labels (Optional), Data tab	every variable chart
Split column	Split Control Limits, on the second tab	every variable chart except Z-MR
Grouping column	GroupBy Order, Data tab	every variable chart
Subgroup ID	Subgroup ID column:, Data tab	the charts that offer the Subgroups group
Part	Part Column, Data tab	Z-MR only

Claiming a column for one role disables it everywhere else. It does not move and it is not unchecked: you have to release the first role before the column becomes available again. That is why a column can appear greyed out in a list for no visible reason.

GroupBy is the one exception. Moving a column into GroupBy Order actively takes it away from the other roles: if it was the measured column, the X-axis label, the subgroup ID, the part column, or the split column, that selection is cleared. Everywhere else the rule is disable, here it is evict.

Two messages can appear in the red line when a claim conflicts:

• "'{0}' is already in GroupBy. Remove it from GroupBy first."
• "'{0}' is already selected as a Data Column. Deselect it from Data Columns first."

Releasing a role does not always make the column usable again in the measurement list. The data type filter still applies, so a column that has been retyped to Nominal stays greyed there even after nothing else is using it.

The GroupBy region

Visible only while GroupBy is selected. It has two lists and six buttons.

Control	What it does
Available Items	Every column that can be grouped on
> and >>	Move the selected items, or all enabled items, into the order list
< and <<	Move items back out
GroupBy Order	The grouping columns, numbered 1., 2., and so on
^ and v	Move the highlighted item up or down

The order matters: the numbers show the nesting, so 1. divides the data first and each later column subdivides what the one above it produced. Every combination of values that actually occurs becomes one chart.

Two rules disable an entry in Available Items:

• More than 100 distinct values. A column with more distinct values than that cannot be grouped on at all, because it would produce more charts than the report can hold. The restriction does not lift.
• Already used elsewhere. A column that is already the thing being measured, the X-axis label, the split column, the subgroup ID, or the part column is disabled here until you release it from that job.

>> moves only the enabled items, so it skips a disabled entry without telling you. Removing a column from GroupBy Order puts it back in Available Items and clears any bucket you chose for it.

Grouping by a date

A column typed DateTime gets an extra drop-down on its row in GroupBy Order, which decides the size of the bucket the dates are collected into. Any other type has no drop-down at all. The choices are:

Year, Month, Week, Day, Hour, Minute, Second

• A bucket is disabled when it would produce more than 100 groups for your data, so on a three-year daily data set Day is not offered and Month and Year are.
• If the column holds no usable dates, every bucket is disabled.
• The first bucket that is legal for your data is chosen for you, and Year is used if none is legal.
• Moving the column out of GroupBy Order clears the bucket. Moving it back in means choosing again.

The metadata line

Clicking any column in any list on the Data tab writes a one-line summary of it at the bottom of the tab. It always reports:

Field	Meaning
Name	The column name, as the Data Selection choices produced it
Type	The data type currently chosen for it
Total Rows	Rows read for this column
Empty	Rows with nothing in them
Invalid	Rows that do not fit the type currently chosen
Unique	Distinct values, shown as >100 once the count passes 100

More fields appear according to the type: a numeric column (Continuous, Integer or Count) adds Numeric, Min and Max, formatted the way the cells are formatted on the sheet; a Nominal column adds Strings; a DateTime column adds Min Date and Max Date.

Invalid is the field to read carefully, because it is counted against the type showing in Type, not against the cells themselves:

Type chosen	What counts as invalid
Continuous	Rows that are not a number
Integer	Rows that are not a whole number
Count	Rows that are not a whole number of zero or more
Nominal	Empty rows only
DateTime	Rows with no usable date

Change the type in Data Types and the same column reports a different Invalid count. That is the fastest way to find out how many cells a type change would cost you.

When the dialog does not open

If the selected range holds no usable data, a message box titled No Data Available appears instead of the chart dialog, with one of two messages:

• "The selected range contains only column headers with no data rows. Please select a range that includes at least one row of data."
• "The selected range contains only empty cells. Please select a range with actual data."

A related rule applies once the dialog does open: any column whose cells are all empty is dropped from every list on the Data tab. It is not shown greyed out, it is simply absent. A column that was entirely hidden behaves the same way when Exclude Data in Hidden Cells is on, because after the hidden cells are dropped nothing is left in it.

Why the dialog closes and reopens

The chart you see while the dialog is open is real, not a sketch. So when you commit a change on the Data tab, Quantum XL closes the dialog, rewrites the worksheets for the new settings, and reopens the dialog with everything you had set still in place. A brief flicker is that cycle, not an error, and nothing you entered is lost.

What counts as committing a change:

• Checking or unchecking a column, choosing a mode, or moving a column into or out of GroupBy Order commits immediately.
• Changing a data type commits immediately.
• Typing in a numeric box commits when you leave the box, and only if the value actually changed after any limit was applied to it.

The cycle is deliberately held back while a choice cannot be honored, so the chart is never rebuilt from a half-made selection: choosing a subgroup ID mode before picking the ID column, or an across-columns mode with only one column checked, waits until the choice is complete.

Reopening the dialog later

Finish stores your dialog settings on the worksheet it creates, and Modify Existing Analysis reads them back so you can change one option without rebuilding the chart from scratch.

Column selections are restored by column name, not by position. Two consequences follow:

• Renaming a column in your source data, or changing the header setting so the names become Col A, Col B and so on, means the stored selection no longer matches and that selection comes back empty.
• Reordering or inserting columns is safe. The names still match, so the same columns are restored even though they have moved.

A stored grouping column is restored even if it currently looks unavailable, and is skipped only when it genuinely cannot be grouped on any more, such as when it now holds more than 100 distinct values.

Limits and Estimation Tab

This tab carries six groups: Estimate Sigma, Transformation, and Historical Values on the left, and Control Limits, Estimate Limits From, and Split Control Limits on the right.

Control limits

The Control Limits group on the Limits & Estimation tab sets how the limits on every panel are obtained.

Control	Type	Default	What it does
Shewhart	radio button	selected	The center line and the limits are computed from the data.
Manual	radio button	not selected	You type the limits yourself, one row per panel.
None	radio button	not selected	No limits are drawn. The points, the center line, the process statistics, and the outlier markers are all still produced.

Manual is not offered on every chart and can be switched off by settings on other tabs. The availability table below covers both.

Choosing None also turns the out-of-control tests off. On a variable chart, blanking the limits blanks every test result as well, so no point is flagged, including by the tests that need only the center line. The zone lines checkbox is not greyed out when you choose None, but ticking it has no visible effect because there are no zone values to show.

Validation: none of the three radios can produce an invalid state, so there is no message.

Math: Control Limits and Zones.

Number of standard deviations (k)

Control	Type	Default	Accepts
Number of standard deviations (k):	text box	3	any number greater than zero, with no upper bound

This is how far the limits sit from the center line, measured in estimated standard deviations. Lower it and the chart flags more points; raise it and it flags fewer.

Editing k also changes the first out-of-control test. That test asks whether a point lies beyond k standard deviations from the center line, and it reads this same box. That is why it is the one test with no parameter of its own: k is its parameter.

It does not move the zone lines. On a variable chart the zone lines are drawn at one third and two thirds of the band, whatever k is, so with k set to 2 the line labelled 1 sigma actually sits at about two thirds of a sigma. The tests that count points inside and outside the zones move with the lines, so they change meaning too.

Where it is hidden. CUSUM has no k box. Its decision interval takes the place of a sigma multiplier.

Validation: blank, non-numeric, zero, and negative entries are all rejected, and the box snaps back to its previous value the moment it loses focus. There is no message, so it is easy to believe an entry was accepted when it was discarded.

Math: Control Limits and Zones.

Manual limits

Selecting Manual enables a grid with one row per panel and the column headings Panel, UCL, Center, and LCL. Each cell is a text box, all of them start blank, and any number is accepted.

Each row is judged on its own, and what you leave blank matters as much as what you fill in.

What a row contains	What that panel does
All three values, with LCL below Center and Center below UCL	Your band is drawn in place of the computed one.
Nothing at all	That panel falls back to computed limits, even though Manual is selected. This is deliberate: it lets you set a location panel by hand and leave the dispersion panel to the software.
One or two of the three	The panel is replaced by a red message where its chart would have been. No chart is drawn for that panel.
All three, but not in increasing order	The same red message replaces the panel.

There is no validation message. The dialog accepts a half-filled row without comment and Finish stays enabled, so the failure appears only in the finished worksheet. Check every row before you press Finish.

Values you type survive a switch away from Manual, but they do not act. Choosing Shewhart or None leaves the grid as you left it and stops it from affecting the run. Switching back to Manual makes those values live again.

Zones and tests follow the band you typed. The zone lines are placed at thirds of your band, computed separately above and below the center, so an asymmetric band gets asymmetric zones. The first out-of-control test means "outside the typed band" rather than any particular multiple of a sigma estimate.

The process statistics are still computed from the data. The mean and the sigma estimates continue to be estimated and continue to be reported in the summary table, even though they no longer draw the band.

Math: Control Limits and Zones.

On Xbar-R the grid has two rows, named Xbar and Range. Filling the Xbar row and leaving the Range row blank is the supported way to fix the band on the means by hand and let Quantum XL compute the range limits, and it is worth doing deliberately rather than by accident: a row with one or two of its three values entered loses that panel entirely.

Historical (known) values

The Historical Values group lets you supply a number instead of estimating it, so the limits describe a process you have already characterized rather than the data in front of you. Every box is a text box, every box starts blank, and blank means estimate it from the data.

Control	Type	Default	What it replaces
Mean:	text box	blank	the mean behind the center line
Standard deviation (overall):	text box	blank	the overall sigma
Standard deviation (within):	text box	blank	the within-subgroup sigma
Mean (between):	text box	blank	the mean of the subgroup means
Standard deviation (between):	text box	blank	the between-subgroup sigma

Which boxes appear depends on the chart, because a box for a quantity the chart never uses would be misleading.

Chart	Boxes shown
Xbar-R, Xbar-S, I-MR	Mean, overall, within
I-MR-R/S	all five
EWMA, CUSUM	Mean, within
Levey-Jennings	Mean, overall

Behavior worth knowing:

• A supplied value wins, and it is applied last. The estimate is computed from the data first and then overwritten, so a First N baseline still selects which points fed the discarded estimate, and still governs anything you did not supply.
• One number can change two. Supplying a within sigma also redefines the between sigma, and supplying a between sigma redefines the sigma of the subgroup means, because the remaining quantity is back-solved from the data.
• A supplied sigma carries no degrees of freedom, so it gets no confidence interval in the capability output. A supplied mean affects no degrees of freedom.
• One value covers every phase. With split control limits on, the same supplied number applies to all phases; there is no per-phase historical value.
• A transformation discards them for that run. Turning on Box-Cox or Johnson greys out the whole group and the values are not used. What you typed reappears if you turn the transformation off.

Validation: none of these boxes is range-checked in the dialog. The one engine check is on Levey-Jennings, which refuses a supplied overall standard deviation that is not a positive number. Anywhere else an unusable value is accepted and shows up as an unusable chart.

Math: Process Sigma Estimation.

A historical mean together with manual limits

These two are not mutually exclusive on most charts, and the result differs by chart. None of the three behaviors is announced, so read the row for your chart before combining them.

Charts	What happens
Xbar-R, Xbar-S, I-MR, I-MR-R/S, EWMA, CUSUM	Both settings act, on different parts of the output. The chart draws the center line you typed in the manual grid, while the summary table reports the historical mean. The two disagree by design, so expect it rather than treating it as an error.
Levey-Jennings	The combination is blocked in both directions. Entering any historical value greys out Manual, and selecting Manual greys out the whole Historical Values group.
p, np, Laney P', c, u, Laney U'	The historical box disappears when you select Manual and its value is ignored for that run, because nothing is estimated under manual limits. Switching back to Shewhart brings both the box and its effect back.

What switches these options off

Four combinations of settings make an option on this tab unavailable. Every one of them acts the moment you type or select, and none of them shows a message, so it is worth knowing them before you go looking for a control that has greyed out.

When this is set	This becomes unavailable
A Box-Cox or Johnson transformation	Manual limits. The radio greys out, and a Manual selection reverts to Shewhart. The Historical Values boxes are also ignored for that run.
Any split mode other than None, whether or not you have entered break points yet	Manual limits, in the same way. Selecting the mode is enough; the gate does not check whether the split produces anything.
A lower or upper specification limit on the Capability tab. A target alone does not do this.	First N subgroups under Estimate Limits From. The selection reverts to All subgroups. Only Xbar-R, Xbar-S, I-MR, and I-MR-R/S have a Capability tab, so only they can reach this.
A transformation and a specification limit together	Split control limits. The whole Split Control Limits group greys out and the mode reverts to None.

The specification-limit gate reads the two specification boxes only. A Target: on its own leaves First N subgroups: available, even though a target on its own is enough to produce the capability output, so it is possible to have a capability block and a frozen baseline on the same chart.

Two chart-level rules sit alongside them: EWMA and CUSUM never offer manual limits at all, and Levey-Jennings treats manual limits and historical values as mutually exclusive, so entering either one greys out the other.

What this setting does

It changes what the limits are estimated from. It never changes what is plotted. Every point always appears on the chart. Asking for the first 25 subgroups does not hide subgroup 26 onward. It means the center line and the control limits are computed from the first 25 subgroups and then drawn straight across the whole chart, so the later points are judged against the earlier baseline. That is the entire purpose of the setting: it is how you freeze a known-good period and watch what happens afterwards.

The same setting carries two labels. It is Estimate Limits From on the variable charts and Baseline Estimation on the attribute and rare-event charts, because those dialogs were written separately. The intent is identical, but the smallest count you may enter differs, and so do a few of the edge cases, so use the block written for this chart.

Estimated from the selected points only	Computed from all the points regardless
The mean behind the center line	Every plotted value
The overall sigma	Each subgroup's own mean, range, and standard deviation
The within-subgroup sigma and everything it is built from	The minimum, the maximum, and the count
The between-subgroup sigma	The observed parts per million outside the specification
The moving-range estimates on an individuals chart	The histogram and the distribution fit
The estimated proportion or rate on an attribute chart	The out-of-control tests, which are applied to every point
The reported degrees of freedom
The transformation itself

Two of those rows surprise people:

• The transformation is fitted on the baseline too. A Box-Cox lambda or a set of Johnson parameters is fitted from the baseline points only and then applied to every row in the data. Change the baseline and you change the transformation, not just the limits.
• The degrees of freedom come from the baseline, so a short baseline widens the capability confidence intervals as well as changing the limits.

With split control limits on there is still only one count. It is reused inside every phase, capped at the length of that phase, so a phase shorter than the count simply uses all of its own points. The count never reaches across a phase boundary, and there is no way to give one phase a different baseline from another.

Math: Baseline and Limit Estimation.

Estimate Limits From

Control	Type	Default	Accepts
All subgroups	radio button	selected
First N subgroups:	radio button	not selected
the count box beside it	text box	blank	a whole number of 5 or more. Its tooltip reads "Minimum 5 subgroups".

The count is in plotted points, not in worksheet rows. On an individuals chart it counts points, and the moving ranges available inside that window are one fewer than the count at the default moving range length, fewer still if there are gaps.

Everything this control does when your entry is not usable, it does silently:

What you do	What happens
Select First N subgroups: and leave the box blank	Exactly the same as All subgroups: every point estimates the limits.
Type a number below 5	Raised to 5 as soon as the box loses focus.
Type a number larger than the data	Every point is used.
Leave a blank subgroup inside the window	It does not use up one of the N. The window reaches further into the data to find real subgroups.
Exclude a point as an outlier inside the window	The same: it does not use up one of the N.

A specification limit switches this off. Type a lower or an upper specification limit on the Capability tab and First N subgroups: greys out and the selection reverts to All subgroups, because a frozen baseline and a capability calculation disagree about which data describes the process. Only Xbar-R, Xbar-S, I-MR, and I-MR-R/S have a Capability tab, so only they can reach this. There is no message, and clearing the specification limit makes the radio available again.

A target on its own does not switch it off. The gate reads the LSL: and USL: boxes only, so a Target: with both specification boxes empty leaves First N subgroups: available. A target on its own is still enough to produce the capability output, so that one combination gives you a capability block and a frozen baseline together.

Every phase still needs at least five usable points. With split control limits on, one phase too short fails the whole analysis with a message instead of a chart, whatever this setting says.

Validation: nothing about this control is ever reported. The count is corrected in place and the analysis runs.

On Xbar-R the count is a count of subgroups, not of worksheet rows, so First N subgroups: 25 with a subgroup size of 5 estimates the limits from the first 125 rows.

Estimate Sigma, subgrouped data

The Estimate Sigma group chooses how the process standard deviation behind the limits is estimated. The estimates differ in how they weight the subgroups and in how much they are disturbed by an unusual one, not in what they are trying to measure.

Control	Type	Default	What it uses
Rbar (average range)	radio button	selected when it is the first method offered	the ranges of the subgroups
Sbar (average standard deviation)	radio button	selected when it is the first method offered	the standard deviations of the subgroups
Pooled standard deviation	radio button	not selected	all the within-subgroup variation pooled together

Each dialog shows only the methods that suit its chart, and the first one shown is the one selected when the dialog opens.

Chart	Methods offered	Default
Xbar-R	Rbar, Pooled standard deviation	Rbar
Xbar-S	Sbar, Pooled standard deviation	Sbar
I-MR-R/S	Rbar, Sbar, Pooled standard deviation	Rbar
EWMA, CUSUM	all three, when the data is subgrouped	Rbar

If the data turns out not to be subgrouped, for example because a subgroup identifier column has a different value on every row, no subgroup method can be evaluated and a moving-range estimate is used instead, whatever the radio buttons show. No message is given.

Validation: this is a closed set of radio buttons, so there is nothing to validate and no message.

Math: Process Sigma Estimation.

Xbar-R offers Rbar (average range), selected when the dialog opens, and Pooled standard deviation. Sbar is deliberately not offered here: the companion panel on this chart is a range chart, so the estimate that pairs with it is built from ranges. Choose Xbar-S if you want the standard deviation form of both.

The unbiased-constants checkboxes

Every estimate of a standard deviation from small samples runs slightly low on average. These two checkboxes decide whether that small bias is corrected. They have different defaults, which is easy to miss.

Control	Type	Default	What it changes
Use unbiased constants (within sigma)	check box	checked	the correction applied to the within-subgroup estimate
Use unbiased constants (overall sigma)	check box	unchecked	the correction applied to the overall estimate

The within checkbox greys out for some methods, because it would do nothing. It has an effect only with Sbar, with the Pooled standard deviation, and with the Square root of MSSD. With Rbar, the Average moving range, and the Median moving range the correction is always part of the estimate, so the dialog disables the checkbox rather than pretending the choice exists.

The overall checkbox is never greyed out, and it is a small correction because it is applied over the whole data set. It moves a drawn limit on one chart only, the Levey-Jennings chart, whose limits come from the overall estimate.

Levey-Jennings does not show either box, and ignores both. Its overall standard deviation is always the uncorrected form.

Validation: checkboxes cannot be invalid, so there is no message. When a correction factor does not exist for the size it would be evaluated at, the correction is skipped and the uncorrected value is reported rather than nothing.

Math: Process Sigma Estimation and Control Chart Constants.

On Xbar-R the within checkbox is disabled under Rbar, which is the default, because the range estimator always applies its own constant. It becomes live only when you select the pooled standard deviation, and there it changes the estimate itself, which moves the limits on both panels and the center line of the Range panel with them.

Transformation

A transformation replaces each measurement with a rescaled version of itself, chosen so the rescaled values sit closer to a normal distribution. Control charts assume a normal distribution and never fit any other one, so a transformation is the only remedy the product offers for skewed measurement data on a control chart.

Charts	Transformation group box
Xbar-R, Xbar-S, I-MR, I-MR-R/S, EWMA, CUSUM	Offered
Levey-Jennings, Z-MR	Not offered. There is no control, and no transformation is applied.
p, np, Laney P', c, u, Laney U', G, T	Not offered. These charts plot counts, proportions, or waiting times and have their own distributions built in.

Controls

The group box is headed Transformation.

Label as shown	Control	Default	Valid entries	What it does
None	Radio button	Selected	n/a	The chart is built from the measurements as entered.
Use Johnson Transformation	Radio button	Not selected	n/a	Fits a Johnson family transformation.
Use Box-Cox Transformation	Radio button	Not selected	n/a	Fits a Box-Cox power transformation. All values used must be positive.
Use Optimal Lambda	Radio button	Selected as soon as Box-Cox is chosen	n/a	The power is fitted from your data.
Enter Custom Value	Radio button	Not selected	n/a	You supply the power instead of fitting it.
(lambda box) with the hint (-5 to 5) beside it	Text box, no label of its own	Empty	A number	The power to use.

Hidden rather than disabled: the Use Optimal Lambda and Enter Custom Value buttons appear only while Use Box-Cox Transformation is selected, and the lambda box and its (-5 to 5) hint appear only while Enter Custom Value is selected. The Johnson transformation takes no parameters, so it reveals nothing.

Validation. The dialog does not check the lambda box against the range in the hint beside it, and it shows no message of any kind. The value you type is passed on as it stands, and the supported range is enforced further in, where the transformation is computed. The two shared math pages define the transformations and the range: Box-Cox Transformation and Johnson Transformation.

What a transformation affects

A transformation is not a display option. It changes the numbers the whole analysis is built from, so read the chart in transformed units afterwards.

Affected	Not affected
The plotted points on every panel	Which points appear, and in what order
The center line, the control limits, and the zone lines	The rules that are switched on, and their thresholds
Every sigma estimate and its degrees of freedom	The sigma multiplier
The vertical axis, which is now in transformed units
The values reported in the summary table
Any specification limits, target, and the capability results computed from them

The transformation is fitted once for the whole chart, and it is fitted on the baseline points only, not on all the data. With splits in effect, the single fit uses the union of the per-phase baseline windows, that is exactly the points that feed each phase's own center line and within-phase sigma, and the fitted transformation is then applied to every row of the chart. Individual phases never get their own transformation. Full detail: Splits and Phases.

Blank rows are handled slightly differently by the two transformations while the fit is being made: Box-Cox keeps a blank as a hole, so the moving range chain breaks in exactly the places it would have broken anyway, while the Johnson transformation drops blanks from the values it fits on.

With a transformation active on an Xbar-R chart, each plotted point is the mean or the range of the transformed values, not the transformation of the mean or of the range. Both vertical axes and every value in the summary table are in transformed units.

Conditional behavior

Condition	Effect
Any transformation is active	Manual control limits become unavailable. The Manual option is greyed out, and if it was already selected it reverts to the calculated limits. Limits typed by hand would be in the original units and there is nothing to convert them with.
Any transformation is active	The Historical Values boxes are greyed out, and any value already typed there is dropped for this run rather than converted. The typed text stays in the box and takes effect again when the transformation is switched back to None.
A transformation is active and a capability analysis is active	Split Control Limits is greyed out entirely and the split mode reverts to None. A capability analysis counts as active as soon as a lower or upper specification limit is entered. This combination can only arise on the charts that offer both a transformation and a Capability tab.
A transformation is active and splits are in effect	One transformation for the whole chart, fitted on the union of the per-phase baseline windows, applied to every row. Both the plotted values and the summary table report transformed results.
Estimate Limits From is set to a first-N count	The transformation is fitted from that baseline subset, not from all the data. Changing the count changes the transformation, and therefore changes every plotted value.
Box-Cox is selected	The Box-Cox transformation is defined for positive values only. Zero and negative measurements cannot be transformed this way.

Split Control Limits

A split divides the chart into consecutive sections, called phases, and gives each phase its own center line and its own control limits. Use it when the process changed on a known date: a new supplier, a tooling change, a settings change. The limits then step at the change instead of averaging across it.

Every phase estimates its own center line, its own sigma, its own control limits, and its own zone lines, and the out-of-control run counters restart at every phase boundary. Splitting never hides or moves a point: all points stay on the chart in their original order, and only the limits they are judged against change. For the formulas, and for the full list of what is shared across the chart versus estimated per phase, see Splits and Phases.

Controls, variable chart dialogs

The group box is headed Split Control Limits and holds three mutually exclusive mode buttons plus the editors each mode reveals.

Label as shown	Control	Default	Valid entries	What it does
None	Radio button	Selected	n/a	One center line and one set of limits for the whole chart.
Split by column	Radio button	Not selected	n/a	A new phase starts at every row where the chosen column's value changes.
(split column list)	Drop-down list, no label of its own	Nothing selected	Any one column offered in the list	Names the column whose value changes drive the phases.
Manual break points	Radio button	Not selected	n/a	Phases start at the point numbers you type.
(break entry box)	Text box, no label of its own. Tool tip: "Enter a 1-based chart point (subgroup) number"	Empty	A whole number from 1 up to the number of plotted points	Holds one break number until you press Add. It is a staging box; typing in it alone changes nothing.
Add	Button	n/a	n/a	Moves the typed number into the break list, in ascending order, and inserts a matching label slot.
Remove	Button	n/a	n/a	Deletes the break selected in the list and its label slot.
(break list)	List box	Empty	n/a	Shows the break point numbers currently in effect.
Split Labels (shown beside each divider):	Label above one text box per phase	One empty box, named "Split 1"	Any text	The text drawn beside each divider on the chart.

Hidden rather than disabled: the split column list appears only while Split by column is selected, and the break entry box, Add, Remove, the break list, and the whole Split Labels block appear only while Manual break points is selected.

Disabled: the entire group box is greyed out, and the mode reverts to None, when a transformation and a capability analysis are both active. See the conditional behavior table below.

Validation, and what it does not tell you. These dialogs have no validation message line in this group box at all. Add silently refuses the entry, leaving it in the box, when it is not a whole number, when it is below 1, when it is at or beyond the known number of plotted points, or when that break is already in the list. Nothing appears on screen in any of those cases. When the point count is not yet known to the dialog the upper check is skipped, so a break past the end of the data can be added and is dealt with later by the calculation. Remove with nothing selected in the list does nothing and says nothing. There is no check at all on how short a phase the break would create.

What a break number means

A break number is the 1-based number of the plotted point that starts the new phase, the same number you read along the horizontal axis, not a worksheet row address. On charts plotted from subgroups it is the subgroup number, not the raw data row. On charts where one row is one point the two are the same.

Breaks must be different from each other and are kept in ascending order for you. A break at point 1 does nothing, because the first phase already starts there.

Split Labels

The Split Labels (shown beside each divider): block gives one text box per phase, so the number of boxes is always the number of breaks plus one. Each box is named Split 1, Split 2, and so on, in chart order. Those names are slot names, not the labels: they are fixed and cannot be edited. Whatever you type in the box beside a slot is what gets drawn on the chart. Leaving a box empty draws no label for that phase.

Adding a break inserts a new empty box at the position that changed rather than adding one at the end, so labels already typed stay with the phases they were written for.

The block appears only in the manual break mode. There is no way to type phase labels when the phases come from a column: in column mode the label beside each divider is the split column's own cell value.

The split column is claimed from the Data tab

The split column is chosen here, but it is one of the worksheet columns listed on the Data tab, and a column can hold only one job at a time. Choosing a column as the split column claims it: on the Data tab that column is greyed out and can no longer be checked as a measurement column, an X-axis label column, a subgroup ID, or a part column. Releasing it here gives it back. A column already claimed for one of those other jobs appears greyed in the split column list and cannot be picked. Neither the greyed check box on the Data tab nor the greyed list entry here explains which job is holding the column.

Selecting the column mode with no column chosen is not an error. It is a deliberate decision in the product, and it means do not split. Nothing is flagged, no message appears, and the chart is built with one set of limits, exactly as if the mode were None. The same is true of the manual break mode with an empty break list.

Minimum phase length, and two opposite outcomes

Every phase has to be long enough to estimate limits from. The minimum differs by chart family, and so does what happens when a break breaks the rule.

Charts	Shortest phase allowed	A break that would create a shorter phase
Variable charts	5 points	The whole analysis is rejected and no chart is produced.
Attribute and rare-event charts	2 points	The break is dropped and the chart is built without it.

That is the same user action with opposite outcomes: on an attribute chart a too-short phase costs you a divider, on a variable chart it costs you the chart.

The variable chart dialogs validate neither number. They do not check the minimum, and they do not check the arithmetic of the phase lengths your breaks imply, so a set of breaks can be accepted without complaint at entry and then fail when the chart is built. The attribute and rare-event dialogs do check the two-point rule as each break is added, with the message shown above.

A variable chart phase also fails the analysis when it holds fewer than five values that are actually present, even when the phase itself is long enough. Blank rows inside a phase therefore matter as much as its length.

On Xbar-R the five-point minimum is five subgroups, and the dialog does not check it, so a break that leaves a phase of four subgroups is accepted here and then stops the analysis with a message instead of producing a chart.

Conditional behavior

Condition	Effect
Any split mode other than None is selected, on a variable chart	Manual control limits become unavailable. The Manual option is greyed out, and if it was already selected it reverts to the calculated limits.
A split mode is selected but produces no phases (column mode with no column, or manual mode with an empty list), on a variable chart	Manual control limits are still unavailable. The check looks at which mode button is selected, not at whether any phase boundary results. Setting the mode back to None restores the Manual option.
Any split mode selected, on an attribute or rare-event chart	No such restriction. Manual limits stay available, and the band you enter is drawn in every phase.
A transformation and a capability analysis are both active	The whole Split Control Limits group box is greyed out and the mode reverts to None. A capability analysis counts as active as soon as a lower or upper specification limit is entered. This can only arise on the charts that offer both a transformation and a Capability tab.
A transformation is active, with or without splits	One transformation is fitted for the whole chart and then applied to every row. Phases never get their own transformation.
Estimate Limits From, or Baseline Estimation, is set to a first-N count	There is one count for the whole chart. It is reused inside every phase and capped at that phase's length, so a short phase uses all of its own points while a longer phase in the same chart uses the count you typed. There is no per-phase count, and the count never reaches across a phase boundary. See Baseline and Limit Estimation.
Out-of-control rules are on	Every run and every window restarts at each phase boundary. A run in progress when a boundary arrives is abandoned, so a run of eight points that straddles a boundary cannot combine into one signal. The point-by-point test against the limits is unaffected, because each point is compared with its own phase's limits.
A historical mean or sigma is supplied	The one value you supply is applied to every phase. It is not a per-phase entry.

Splits are edited after the fact in the Control Chart task pane as well, but only the manual break points and the labels. The column mode cannot be selected or cleared there.

Rules and Display Tab

Out-of-Control Rules

The group box headed Out-of-Control Rules holds one row per rule. Each row is a check box carrying the rule's description, followed by up to two small numbered boxes labelled N = and M =. N is how many points the rule needs, and M, where a rule has one, is the length of the window those points must fall inside.

Ticking a rule adds its test to the analysis. Nothing else about the chart changes: the center line, the limits, and the plotted points are the same whether a rule is on or off.

Thresholds. Every box arrives pre-filled with that rule's standard value rather than blank, so you can see what the rule will do before you change it. Clearing a box means use the standard value; it does not mean zero. Unticking a rule leaves its numbers visible but locks the boxes, so the value you set is still there when you tick the rule again.

There is no message when a threshold is refused. On the attribute and rare-event dialogs a count below 2 is silently raised to 2 as soon as you leave the box. On the variable chart dialogs a value that is blank, zero, or negative is treated as the standard value.

The rule set on the variable charts

Eight rows, and all eight are ticked by default. This is the opposite of the attribute charts, so a chart of the same data can flag very differently depending on which family of chart you chose.

Row label as shown	Parameters and defaults	Default
Rule 1 - Beyond K sigma from center	none, see the note below	On
Rule 2 - N consecutive points on same side of center	N = 9	On
Rule 3 - N consecutive increasing or decreasing	N = 6	On
Rule 4 - N consecutive alternating up/down	N = 14	On
Rule 5 - N of M beyond 2 sigma (same side)	N = 2, M = 3	On
Rule 6 - N of M beyond 1 sigma (same side)	N = 4, M = 5	On
Rule 7 - N consecutive within 1 sigma	N = 15	On
Rule 8 - N consecutive beyond 1 sigma (either side)	N = 8	On

Rule 1 has no parameter box of its own. It tests against the drawn control limits, so its width is the sigma multiplier from the Control Limits section.

What each rule actually tests, and which points of a run get marked, is defined on Out-of-Control Rules.

Xbar-R shows all eight rows, and all eight are on when the dialog opens.

Which panels the rules run on

Every panel is checked, the dispersion panels included. On a two-panel or three-panel chart the range, standard deviation, and moving range panels each run their rules over their own plotted values, against their own center line and their own limits.

Rules 5 through 8 are the exception. They read the zone lines and assume a symmetric spread around the center line, which a range or a standard deviation does not have, so they run on the location panel only.

Panel	Rules that run there
Xbar, Individuals, or EWMA (the location panel)	Every rule the chart offers
Range, standard deviation, moving range	1, 2, 3, 4
Z-MR moving range panel	1, 2, 3
Single-panel charts	Every rule the chart offers

What the group box does about it depends on which panels the chart is drawing:

• On a variant that draws a dispersion panel only, such as R only, S only, or Moving Range only, the rows for rules 5 through 8 are greyed out along with their threshold boxes. Greying them does not clear them: whatever you had ticked is still ticked if you switch the panel view back.
• On a chart that draws the location panel next to a companion panel, those rows stay available and an italic note appears under the list reading "Rules 5-8 only apply to" followed by the name of the location panel.

On Xbar-R the location panel is the Xbar panel and the companion is the Range panel, so rules 1 through 4 are tested on both and rules 5 through 8 on the Xbar panel only. With the Xbar-R or Xbar only variant selected those four rows stay available; select R only and they grey out, because there is no location panel left to test.

The sigma multiplier is also a rule setting

Rule 1 tests each point against the drawn control limits, so editing the number of standard deviations in the Control Limits section changes the Rule 1 test at the same time as it changes the limits. That is why Rule 1 has no threshold box of its own. On the variable charts it also moves the zone lines, and therefore changes what rules 5 through 8 test.

Conditional behavior

Condition	Effect
Control limits set to None, on a variable chart	No rule fires. Every rule result is cleared along with the limits, so no point is marked even though the rules are still ticked.
Control limits set to None, on an attribute or rare-event chart	The center line is still estimated, so rules 2, 3, and 4, and Rule 9 on a G chart, still fire and still mark points. Rule 1 cannot fire, because there are no limits to exceed.
Control limits set to Manual	The rules run against the band you entered, and the zone lines are derived from that band.
Manual limits entered with the center left blank, on an attribute chart	There is no center line and no zone lines, so rules 2, 3, and 4 cannot fire.
Splits are in effect	Every run and every window restarts at each phase boundary. A run in progress when a boundary arrives is abandoned and cannot combine with the run that starts after it.
A point is blank or excluded	Runs break at the gap rather than bridging it. For the two window rules, rules 5 and 6, a blank invalidates every window that overlaps it, not just the run.
A rule is unticked	Its threshold value is kept and its box is locked. Nothing is lost by turning a rule off and on again.
The sigma multiplier is changed, on a variable chart	The zone lines move with the band, because they are placed at thirds of it. At a multiplier other than 3 the line labelled 2 sigma is not at 2 sigma, which changes what rules 5 through 8 test. On the attribute charts and Z-MR the zone lines are at a true 1 and 2 sigma at any multiplier.
A capability analysis or a transformation is active	Neither affects the rules. The rule set, the thresholds, and the panels checked are the same.

Background reading for your operators: Out-of-Control tests.

The chart does not tell you which rule fired

Every rule you tick is tested, and the results are combined into a single verdict per point: this point broke at least one enabled rule, or it did not. Points that broke one are drawn in a different color from the rest, and that is the whole of the report. There is no per-rule label, no per-rule marker, no per-rule column, and no list of violations anywhere in the chart or the worksheet. A point that breaks four rules at once looks exactly like a point that breaks one, and the output never names either.

So when you turn several rules on, read a marked point as an instruction to go and look at the chart, not as a diagnosis. If you need to know which pattern caused a particular signal, the practical method is to switch the other rules off and rebuild the chart.

Display Options

The Display Options group box holds two features: the sigma zone lines, and reference lines of your own at Y values you choose. It is the same group box on every control chart. The variable charts take it from a shared control, and the p, np, Laney P', c, u, Laney U', G, and T dialogs repeat the same block with the same labels.

• Show 1-sigma / 2-sigma zone lines: draws four light grey lines inside the control band, two above the center line and two below, dividing each side into three zones. The checkbox is cleared by default.

The zone lines are always built into the chart. This checkbox only decides whether they start out visible, so they can be shown or hidden later from the Analysis Pane without running the analysis again.

Where the lines are placed is not the same on every chart, and on a variable chart drawn with a sigma multiplier other than 3 the names 1-sigma and 2-sigma do not describe where the lines actually sit. Since several of the out-of-control tests measure a point against these zones, this changes what those tests count. The placement rule for each chart family is on Control Limits and Zones.

The two dialog families treat the checkbox differently when Control limits is set to None. On the variable charts the checkbox stays available, but with no control band there is nothing to divide into zones and no lines are drawn. On the attribute and rare event charts the checkbox is disabled and cleared for you.

Reference lines

A reference line is a horizontal line at a Y value you supply: a specification limit, a target, a contract threshold, anything you want the points compared against. Until you add one the editor reads "No reference lines configured. Use the row editor below to add Y-value reference lines."

Each reference line is one row with four editable cells and a remove button:

Cell	What it sets	Default
Value	the Y position of the line	0
Label	the legend entry for the line	blank
Color	the line color, picked from a color button	red
Thickness	the line weight, chosen from 0.5, 1.0, 1.5, and 2.0	1.0
X	removes that row. Its tooltip reads "Remove this reference line"	n/a

Value is not validated. Type something that is not a number and the cell keeps the value it had. A blank Label keeps the line out of the chart legend; the line is still drawn, under a generated name built from its value. The editor scrolls on its own once the list of rows is taller than the space allowed for it.

• Add Reference Line: appends a blank row and refreshes the chart preview by itself. Removing a row with its X button does the same.
• Apply: commits edits to Value, Label, Color, and Thickness, which do not refresh the preview on their own. Its tooltip reads "Refresh the chart preview to reflect any pending reference-line edits". The button appears only once at least one reference line exists, and does nothing when there is nothing outstanding to commit.

So adding and removing lines is immediate, while editing an existing line needs Apply.

Reference lines are drawn on the location panel only

Reference lines appear on the panel that plots the measurement itself: the Xbar panel, the Individuals panel, the EWMA panel, or the Z panel of a Z-MR chart. The dispersion panels (Range, Standard Deviation, Moving Range) are in different units, so they never carry reference lines. The location panel's Y axis is stretched to include every reference line value, so a line outside the data still shows.

This has a consequence on the single-panel dispersion charts. R only, S only, and Moving Range only draw no location panel, so a reference line entered in the editor never appears anywhere on the chart. The editor still accepts it and still lists it. If you need a reference line against a range or a standard deviation, there is no dialog option that will draw one.

CUSUM is the exception: it is a single overlay chart rather than stacked panels, and it draws reference lines on that chart.

On Xbar-R the location panel is the Xbar panel, so a reference line for a specification limit or a target lands where you expect it. Under the R only variant there is no Xbar panel, and a reference line you enter is never drawn.

Layout you do not choose

Nothing else about the appearance of the chart is a dialog option. These are fixed:

• Which panels are drawn comes from the ribbon entry you started from, not from a checkbox in the dialog. Choosing R rather than Xbar-R is how you get the range panel on its own.
• Panel titles are composed for you from the panel type, the group, and the measurement column name, with empty parts dropped.
• Plot order is fixed, and it is also the front-to-back order: the data line, then the zone lines, then the upper and lower control limits, then the center line, then the reference lines. The zone lines are added before the limits deliberately, so they stay in the background.
• Axes are set for you. The X axis is numbered by plotted point and titled Subgroup. The Y axis is scaled to fit every plotted value, including the zone lines and, on the location panel, the reference lines; dispersion panels are held at or above zero. When a chart has more than one panel the panels are aligned with each other so their points line up vertically.

Once the chart exists, the zone lines can be shown or hidden from the Analysis Pane without running anything again. Reference lines cannot: they are not in the pane, so to add, edit, or remove one you modify the analysis and run it again.

Capability Tab

The Capability tab attaches a capability analysis to the chart. It holds five groups: Specification Limits (LSL:, Target:, and USL:), Process Capability Standard, the capability Confidence Intervals, Goodness of Fit, and the histogram bin settings.

Nothing on this tab produces output until you enter a specification limit or a target. With all three boxes empty the settings are still stored, but no capability block and no histogram are written to the worksheet, no capability index is reported, and the goodness-of-fit test does not run even though a method is selected. Entering a lower specification limit, an upper specification limit, or a target is what switches the whole block on.

Two interactions belong to this tab rather than to the capability settings themselves:

• Entering a specification limit switches First N subgroups off. Type a value in LSL: or USL: and, on the Limits and Estimation tab, the First N subgroups: radio greys out and the selection returns to All subgroups, with no message. Clearing the specification limit makes it available again. A Target: on its own does not do this, even though a target on its own is enough to produce the capability output, so a target with both specification boxes empty gives you a capability block and a frozen baseline at the same time.
• A specification limit together with a transformation switches splits off. The whole Split Control Limits group greys out and the split mode returns to None.

One difference from the standalone tool is worth stating: a control chart never fits a distribution other than the normal. There is no fit-type choice on this tab and no distribution comparison table in the output, because the chart's model is normal by definition. If your measurements are badly skewed, the remedy on a chart is the Transformation group on the Limits and Estimation tab, not a different fitted distribution.

Every one of these groups is the same control as in the Capability Analysis tool, and the settings are described in one place, on the Capability Analysis and Histogram Options page. Read the Capability Options sections there for the capability standard, the confidence intervals, and the goodness-of-fit tests, and ignore the distribution fitting and plot order sections, which the chart does not offer.

Task Pane

The Analysis Pane

When a control chart has been created, Quantum XL docks a task pane titled "Control Chart" against the right side of the Excel window. There is one control chart pane in the product. Every chart type gets the same pane with the same three sections, Window, Display, and Split Control Limits, so nothing in it is specific to the chart you ran.

Only one analysis pane is shown at a time. The same ribbon button serves the Capability and Histogram pane, and opening one hides the other.

The pane is not a second copy of the chart dialog. It gives you a display window, three display switches, and the manual split editor. Everything else stays in the dialog: the data selection, the limit type, the sigma multiplier, the baseline, the sigma estimation method, the transformation, the historical values, the reference lines, and the individual out-of-control tests.

On an Xbar-R sheet, that is the worksheet named Xbar-R Chart, and both of its panels are redrawn together by every pane setting.

Opening and closing it

The ribbon button is labelled Analysis Pane, in the Statistical Tools group, while the pane itself is titled "Control Chart". They are the same thing under two names.

• The pane opens by itself every time an analysis finishes, not only the first time.
• The ribbon button is enabled only on a sheet that holds a Quantum XL analysis. On any other sheet it does nothing.
• Moving to a sheet with no control chart on it does not close the pane. Every section greys out and the pane stays where it is; going back to a chart sheet enables it again.
• Once you close the pane, moving to another chart sheet does not bring it back. Reopen it with the Analysis Pane ribbon button, or by running another analysis.

It applies to the worksheet, not to one chart

The pane is bound to the active worksheet rather than to a chart you selected. If the worksheet holds several control charts, everything you change in the pane is written to all of them. The pane says so itself: under the sheet name it reports how many control charts it found, and the split section carries a warning line reading "Applies to all charts of this analysis".

Two details are worth knowing:

• The number it reports is a count of the hidden data sheets that belong to the worksheet, one per chart, not a count of the chart objects you can see. A chart whose data sheet was never written, or was cleaned up, is not counted, so the number can be lower than the number of charts on the sheet.
• The settings the pane displays are read from the first chart on the sheet, while its checkboxes are written to every chart. If the charts on one sheet have been changed individually, the pane shows you one chart's state and applies it to all of them.

Window (pane only)

No chart dialog anywhere in Quantum XL has a display window. This section is the only place it can be set.

• Start at: the first plotted point shown, counted from 1.
• Size: how many points are shown. The box is a drop-down offering 50, 100, 500, and 1000, and you can type any other number into it. A new chart opens showing the last 1000 points, or all of them if there are fewer.
• The two Page buttons, one marked with a left arrow and one with a right arrow, move the window back or forward by one full window width.

Start at and Size are applied when you press Enter, press Tab, or click outside the box, so picking a size from the drop-down list takes effect when you leave the box. The Page buttons act on the click. A window that runs past the data is pulled back into range, so paging forward stops at the last point. Changing Size while the window is sitting at the end of the data keeps it at the end; otherwise the starting point is left where it was.

Changing the window redraws the charts over a different range of points. Nothing is recalculated: the control limits, the center lines, and the out-of-control flags were all worked out and stored when the chart was built, so they do not change as you scroll.

Display

• Show zone lines: the same setting as "Show 1-sigma / 2-sigma zone lines" in the dialog's Display Options group. The zone lines are always built into the chart, so this shows or hides lines that are already there.
• Show out-of-control indicators: a coarser version of what the dialog offers. In the dialog you enable the out-of-control tests one at a time; this single checkbox shows or hides the markers for all of them at once. It cannot switch a test back on, because it only filters what the analysis already flagged, so a test the dialog had turned off stays off. To change which tests run, modify the analysis. See Out-of-Control tests.
• Show outlier markers: pane only. No chart dialog has an outlier display option. When it is checked, a point you excluded as an outlier is drawn as a hollow marker so you can pick it out; when it is cleared, that point is drawn filled like any other.

All three take effect the moment you click them, and all three only change how the existing chart is drawn.

Split Control Limits

This section covers part of what the dialog's Split Control Limits group covers: the manual break points and the phase labels, and nothing else.

• Manual Break Rows (1-based, start of split): type the point number at which a new phase begins and choose Add. The row has to be between 1 and the number of plotted points, it cannot repeat a row already in the list, and the pane itself checks only that the break leaves at least two points in a phase. A row that fails one of those checks is refused and the reason is printed in red under the editor.
• The effective minimum phase length is whatever the chart's engine requires, which is five points on the variable charts. The pane's own check is the two-point one above, so on a variable chart the pane will accept a break that leaves a phase of two, three, or four points and the engine will then refuse to recompute. Nothing is shown when that happens: the break rows simply return to the ones the chart was built with. Use the minimum stated on the chart's own page, not the pane's, when you place a break.
• The list shows the break rows in order. Select one and choose Remove Selected to take it out.
• Split Labels: one box per phase, always one more box than there are break rows, shown beside each divider on the chart.

What the pane cannot do is choose or clear splitting by a column. If the analysis was split by a column the whole section greys out and the pane reads "Splits driven by column: column name. Use Modify Analysis to switch to manual breaks." Switching between splitting by a column, splitting at manual break points, and not splitting at all is a dialog decision.

If the pane cannot find the stored settings for the chart it reads "No analysis settings found for this chart." and the section stays disabled.

Apply Splits (pane only)

The dialog has no apply button for splits on its own; its Finish button commits the whole dialog. In the pane, break rows and labels do nothing until you choose Apply Splits, and the button stays disabled until they differ from what the chart was built with.

Apply Splits does far more than anything else in the pane. It re-reads the source data, runs the entire analysis again, and rebuilds the analysis worksheets rather than editing them. Expect it to take about as long as creating the chart did.

Splitting is not allowed on every analysis. If the analysis rules it out, for example when you entered manual control limits, or combined a transformation with a capability analysis, the recompute is rejected and the pane goes back to the break rows the chart already had.

On Xbar-R, Apply Splits is rejected when the chart was built with manual limits, or with a transformation and a specification limit together. Both are the combinations the dialog already refuses to split.

What is in the pane, and what is only in the dialog

Pane control	Also a dialog option?
Window: Start at, Size, the two Page buttons	No. Only in the pane; no dialog has a display window.
Show zone lines	Yes. The same setting as "Show 1-sigma / 2-sigma zone lines" in Display Options.
Show out-of-control indicators	Partly. The dialog enables the tests one at a time; the pane shows or hides all of their markers at once.
Show outlier markers	No. Only in the pane.
Split Control Limits: break rows and split labels	Partly. Manual break points and labels only; splitting by a column can be neither chosen nor cleared here.
Apply Splits	No. Only in the pane.

Everything else that shapes the chart is a dialog option with no representation in the pane: the data selection, the limit type and manual limits, the sigma multiplier, the baseline, the sigma estimation method, the transformation, the historical values, the reference lines, the individual out-of-control tests, and the split mode itself.

What each change costs

Change	What happens
Start at, Size, either Page button	The charts are redrawn over a different range of points.
Show zone lines, Show out-of-control indicators, Show outlier markers	The lines and points already on the chart are reformatted.
Apply Splits	The whole analysis is computed again and the analysis worksheets are regenerated.

The window and the three checkboxes are immediate and change nothing statistical. Apply Splits is the only action in the pane that can change a number on the chart.

It is saved with the workbook

Every pane setting is stored in the workbook: the display window, the three display switches, and the break rows with their labels. Save the workbook, close it, and open it again, and the charts come back exactly as you left them, on the same window, with the same lines shown or hidden. When you next open the pane it fills its own boxes in from the chart.

The pane itself does not come back on its own when the workbook is opened. Open it with the Analysis Pane ribbon button.

There is no undo in the Analysis Pane

Nothing you do in the pane can be reversed with Ctrl+Z. Excel does not record the changes Quantum XL makes to a chart, so the usual undo shortcut will not restore a display window, a checkbox you cleared, or a break row you removed. Put the value back by hand.

Apply Splits goes further: because it deletes and rebuilds the analysis worksheets, it clears Excel's undo history for the workbook outright, so nothing you did before it can be undone either. Save the workbook before you use Apply Splits.

The Buttons at the Bottom

The buttons at the bottom

Four buttons sit below the tabs on every control chart dialog. The worksheets you can see behind the dialog are a preview, and three of the four buttons decide what happens to them.

Button	What it does
Back	Deletes the preview worksheets and reopens the Data Selection window with your previous range still filled in. Use it to change the range, the orientation, or the header setting.
Help	Opens the help page for this dialog, and falls back to the copy installed with Quantum XL when no internet connection is available.
Cancel	Deletes the preview worksheets and ends the analysis. Nothing is left on the workbook.
Finish	Keeps the worksheets as they stand and stores your dialog settings on the worksheet, so Modify Existing Analysis can reopen this dialog later with everything as you left it.

Closing the dialog with the window X, or with Alt+F4, does the same as Cancel.

Finish is unavailable while a selection on the Data tab cannot be honored. If it is greyed out, check the Data tab for a red message and for a mode whose column has not been chosen yet.

See Also

• Xbar-R
• Xbar-R Math Details
• Out-of-Control tests
• Capability Analysis and Histogram Options