How does the extrapolation of blocks (AutoFill) work?

A horizontal or vertical series in a block can be extrapolated by dragging the block Fill Handle (a small solid square 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, ).

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'), then this text label is copied into the extended block. If the block contains several different text labels and their numeric values are non-identical, then the text labels are extended by linear regression. If the block contains several different text labels and their numeric values repeat, then these values are duplicated in the extended block.

  • If a variable in the block contains dates (i.e., you selected Date in the Display format group on 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 (i.e., not dates) 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). The syntax for specifying these names is given below (note that it does not matter whether you use upper case or lower case letters, however you need to be consistent throughout the series; e.g., use Jan, Feb, Mar, ..., not Jan, feb, Mar, ...):

Months. The names of months can be spelled out or abbreviated in the following manner:

  • January, February, March, April, May, June, July, August, September, October, November, December

  • Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec

Days. The names of the days can be spelled out or abbreviated in the following manner:

  • Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday

  • Mon, Tue, Wed, Thu, Fri, Sat, Sun

  • M, Tu, W, Th, F, Sa, Su

Quarters. The names of quarters of the year can be specified as follows in the variable:

  • Q1, Q2, Q3, Q4

Custom lists. You can also create your own list of values to use in extrapolating values. See Can I Create a Custom List to Use for Extrapolation?.

Extrapolating (AutoFilling) a block upwards or to the left. In the same manner as extrapolating a block down or right, a block can be extrapolated by dragging the Fill Handle up or to the left past the original start of the block.

If you drag the Fill Handle up or to the left and stop within the original selection without going past the top or left side of the selection, you will delete data within the selection (data to be deleted are indicated in gray as you drag within the selection). You can use the Fill/Standardize Block commands on the spreadsheet Edit menu to copy to adjacent cells within the currently selected block.