How does Extrapolate (AutoFill) work?

How does Extrapolate (AutoFill) work?

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Article ID: KB0081717

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Updated On:

Products Versions
Spotfire Statistica 13.0 and above

Description

This article explains the Extrapolate (AutoFill) feature in Statistica. A horizontal or vertical series in a block can be extrapolated by dragging the block's Fill Handle (a small solid black box located on the lower-right corner of the block). After selecting the block, point at the Fill Handle. When the mouse pointer changes to a plus sign, drag to the last cell(s) to which you want to extrapolate the data. Statistica can create series of values such as sequential numbers, linear extrapolations, and dates (e.g., you can extend a series such as 1, 2, 3 to include 4, 5, 6).
 

Issue/Introduction

How does Extrapolate (AutoFill) work?

Resolution

You can extrapolate (AutoFill) a block in the following ways:

  • If the initial selection contains repeated values, these values are duplicated in the extended block.
  • Non-identical values are extended by linear trend regression to compute extrapolated values for the series.
  • If the block contains the same text labels (i.e., all the cells have the text label 'Gender'), this text label is copied into the extended block. If the block contains several different text labels, then the text labels (beginning with the numeric value of the last text label in the block) are extended by linear regression to compute extrapolated values for the series.
  • If a variable in the block contains dates (i.e., Date is selected in the Display format group box in the Variable specifications dialog), then based on the pattern of dates, Statistica extrapolates the dates appropriately.
  • If a variable in the block contains text names of months (e.g., Jan, Feb, Mar,), days (e.g., Mon, Tue, Wed,), or quarters (e.g., Q1, Q2,), then Statistica extrapolates either up, down, or to the left or right of the block the rest of the names in the series (e.g., Apr, May, ..., Dec; Thr, Fri, Sat, Sun; or Q3, Q4, respectively). Note that it does not matter whether upper case or lower case letters are used, however they need to be consistent throughout the series; e.g., use Jan, Feb, Mar, ...; not Jan, FEB, mar, ....
  • You can also create your own custom list of values to use in extrapolating values. Select Custom Lists in the left pane of the Options dialog (accessible by selecting Options from the Tools menu.
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