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Time Series

Analyze data collected over time: fit and forecast trends, smooth out noise, and measure how values relate to their own past or to another series.

Worked examples

The How-To pages build this chart step by step from sample data, one walkthrough per data layout the tool accepts. Start there if you would rather see a finished result than read the settings.

Quantum XL's Time Series menu contains six tools in two groups:

Smoothing and forecasting (dialog: Time Series Smoothing)

Correlation over time (dialog: Time Series Correlation)

All six take numeric data columns in time order. Each tool's page lists every option in its dialog.

What the sheet records about your settings

The User input box in the top left of the worksheet does not only echo the columns you picked. Under a Settings heading it also states the options that produced the chart below it, so a sheet opened a year later says what it was built from rather than leaving you to guess which boxes were ticked.

This matters most where the choice leaves no other trace. Two Pareto charts drawn from the same data, one grouping the small categories into an "Others" bar and one dropping them, look like two different data sets unless the sheet says which was done.

Two rules decide what appears:

  • Every selector and checkbox is printed on every run, whether or not you changed it from the default. A reader who sees nothing cannot tell a default from a setting the product does not report, so the box states all of them.
  • A value you had to type is printed only when you typed it, and so is a setting that only means something once another box is ticked. Its absence is the answer.

The worksheet is protected

Under the last block in column A, in small italic text, the sheet carries one note:

This worksheet is protected to prevent accidental changes. To unprotect it, select the Review tab and then Unprotect Sheet.

Every analysis worksheet Quantum XL writes is protected, and every one carries this note. The wording is the same on all of them. Protection is there so that a click or a stray keystroke cannot overwrite a number the chart is drawn from, or move a chart off its anchor.

Three things are still allowed while the sheet is protected: formatting cells, formatting columns, and formatting rows. So you can widen a column, change a number format, or restyle a heading without unprotecting anything. Editing a value, editing a chart, and everything else are blocked.

For those, unprotect the sheet from Excel's Review tab, exactly as the note says. The protection carries no password, so Unprotect Sheet takes it straight off without asking for one.

Under Settings, this tool records only the parameters the smoothing method you chose actually used. Printing a moving average's stored smoothing constant would name a parameter that had no part in the fit, so it is left out.

Method Rows
Trend Analysis Trend type, reading Linear or Quadratic, and Forecast points
Moving Average Running length
Double Exponential Smoothing Level (Alpha), Trend (Gamma) and Forecast points

A correlation run records instead:

Row What it reads
Lag type Auto or Manual
Lag value the number you typed, printed only when the lag type is manual

The autocorrelation and partial autocorrelation tables also carry Upper CL and Lower CL columns. A cross-correlation table does not: the engine produces no bounds for it. The level behind those bounds is fixed at 95 per cent and is named in the chart title, which reads (95% significance limits).

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