DOE Charts¶
Ten charts are available from QXL DOE New > Charts, grouped in the menu as Analysis and Regression Diagnostics.
Before anything can be charted there has to be something to chart from: either a design sheet with responses entered, or a regression sheet produced by running a regression on one. Which of the two a chart can use is set out in Chart Source, and it is the first thing to understand about this family.
Parse for Monte Carlo is not one of these ten
The Analysis group of the ribbon holds a Parse for Monte Carlo button next to the Charts menu, and it is easy to read as an eleventh chart. It is not on the Charts menu and it draws nothing: it reads the model on a regression sheet and writes an IPO sheet for the Monte Carlo tools, which is where it is documented. See The QXL DOE New ribbon.
Analysis¶
| Chart | What it shows |
|---|---|
| Pareto of Regression Coefficients | One bar per term, the size of its coefficient, largest first, coloured by p value |
| Interaction Plots | The response against one factor, with a separate line for each level of a second, so non-parallel lines reveal an interaction |
| Main Effects Plots | The response against one factor at a time |
| Thumbnail Plot | A grid with main effects on the diagonal and interactions off it, the whole model on one sheet |
| Surface Plot | The fitted response over two factors as a three dimensional surface |
| Contour Plot | The same surface from above, as lines of equal response |
| Trellis | Any of surface, contour or interaction, repeated across slices of one or two other factors |
| Cube Plot | The corners of a square or cube, labelled with the response there |
Regression Diagnostics¶
| Chart | What it shows |
|---|---|
| Observed vs Predicted | Measured response against fitted value, one point per run, with a 45 degree line |
| Residual Plots | What the model failed to explain, plotted several ways, including studentized residuals, leverage and Cook's D |
What they have in common¶
Nine of the ten open the same dialog: an Outputs tree on the left for choosing what to chart, the chart's own options on the right.
Residual Plots is the exception. It still runs the older dialog, which puts the same three-level tick tree inside a dropdown labelled Source for the plots: instead of in a pane down the side, and has different buttons, so the descriptions in this section apply to the other nine. See Residual Plots.
The left side of the dialog is a box headed Outputs holding a tree with three levels: the worksheet, then each output on it, then each level of that output. Tick the levels you want a chart for. The dialog opens with every level on the active sheet already ticked.
The two upper levels are three-state. Ticking a worksheet or an output ticks everything under it, and clearing it clears everything under it. When only some of the children are ticked, the parent shows a partial state rather than a tick, so the tree tells you at a glance whether a selection is complete.
One worksheet at a time. Ticking anything on a second worksheet silently clears every tick on the one you had selected, and the options on the right rebuild for the new sheet. There is no warning and no way to draw charts from two source sheets in one Create.
If you press Create with nothing ticked, the dialog tells you At least one chart must be selected. and stays open.
If the options you chose produce no drawable chart, the dialog reports There are no valid charts selected for the report. and writes nothing. Where the reason is specific, for example an axis rule or a source restriction, that more specific message is shown instead.
Creating with the dialog left open lets you build several charts from one set of options without reopening it. The charts are identical either way: the only difference is whether the window closes afterwards.
While charts are being written, a status line reports what is happening and a progress bar appears only when more than one chart is being drawn, since a bar for a single chart would sit at 100 percent from the moment it appeared.
Cancel stops the run cleanly between charts, not part way through one. A chart that has already been written stays; the sheet that was mid-write is deleted rather than left half finished. So cancelling never leaves a partial chart behind, but it can leave fewer sheets than you asked for.
The dialog is owned by the Excel window, so Excel cannot cover it while it is open. If it seems to have vanished, it is on another monitor rather than behind the workbook.
Each chart writes a new worksheet placed immediately to the right of the sheet it came from, with the source sheet named in its heading rows. Residual Plots is the exception that writes two sheets, a chart sheet and a text report.
How the sheets are named¶
Six of the ten append the output level's name to the chart name, and the other four do not. Three of the ten also write a different form of the chart's name than the menu uses:
| Chart | Sheet name |
|---|---|
| Surface Plot, Contour Plot, Thumbnail Plot | chart name - output level name |
| Interaction Plots | Interactions Plot - output level name, with the sheet saying Interactions Plot where the menu says Interaction Plots |
| Residual Plots | Residual Plot - output name, singular on the sheet where the menu is plural |
| Main Effects Plot | Main Effects Plot - source sheet name, the same form with the source sheet's name in place of the output level's |
| Cube Plot, Observed vs Predicted | the chart name on its own |
| Pareto of Regression Coefficients | Pareto, on its own, not the full menu name |
| Trellis | the name of the chart type inside it, in the same appended form |
Three of the names are not the menu wording, so search the tab names for the words above rather than for the command you clicked.
The sheet name does not tell you which mode drew it. A single Surface Plot, a grid of them and a trellis of them all land on a sheet called Surface Plot - output level name. If you need to know, the sheet's own heading rows name the source and the chart.
Excel adds (2), (3) and so on when a name is already taken, so repeating a command does not overwrite the earlier sheet.