Difference between revisions of "Documentation/How Tos/Calc: FORECAST function"
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<tt>'''FORECAST(new_xvalue; yvalues; xvalues)'''</tt> | <tt>'''FORECAST(new_xvalue; yvalues; xvalues)'''</tt> | ||
: <tt>'''yvalues'''</tt> and <tt>'''xvalues'''</tt> are single row or column ranges specifying points in a set of data. <tt>'''yvalues'''</tt> and <tt>'''xvalues'''</tt> must be the same size. | : <tt>'''yvalues'''</tt> and <tt>'''xvalues'''</tt> are single row or column ranges specifying points in a set of data. <tt>'''yvalues'''</tt> and <tt>'''xvalues'''</tt> must be the same size. | ||
| − | : <tt>'''FORECAST'''</tt> fits a straight | + | : <tt>'''FORECAST'''</tt> fits a straight line through these data points, using the linear regression method. |
: <tt>'''FORECAST'''</tt> returns the y value on the straight line found, corresponding to the x value in <tt>'''new_xvalue'''</tt>. It is equivalent to <tt>'''TREND(yvalues; xvalues; new_xvalue)'''</tt>. | : <tt>'''FORECAST'''</tt> returns the y value on the straight line found, corresponding to the x value in <tt>'''new_xvalue'''</tt>. It is equivalent to <tt>'''TREND(yvalues; xvalues; new_xvalue)'''</tt>. | ||
Revision as of 19:04, 12 June 2008
FORECAST
Fits a straight line to data using linear regression and returns a point on that line.
Syntax:
FORECAST(new_xvalue; yvalues; xvalues)
- yvalues and xvalues are single row or column ranges specifying points in a set of data. yvalues and xvalues must be the same size.
- FORECAST fits a straight line through these data points, using the linear regression method.
- FORECAST returns the y value on the straight line found, corresponding to the x value in new_xvalue. It is equivalent to TREND(yvalues; xvalues; new_xvalue).
- Advanced topic:
- The parameters xvalues and yvalues are always evaluated as array formulas. Note that TREND does not evaluate its parameters as array formulas.
Example:
FORECAST(6; B2:B6; A2:A6)
- where the x values in A2:A6 are 1, 2, 3, 4, 5 and the y values in B2:B6 are 2, 4, 7, 8, 11 returns 13.
TREND(B2:B6; A2:A6; 6)
- with the same x values and y values, also returns 13.
