# Difference between revisions of "Documentation/How Tos/Calc: TREND function"

## TREND

Fits a straight line to data using linear regression and returns points on that line.

### Syntax:

TREND(yvalues; xvalues; new_xvalues; type)

yvalues and xvalues are single row or column ranges specifying points in a set of data.
TREND fits a straight line through these data points, using the linear regression method.
If type is 0 the straight line found will pass through the origin; if type is non-zero or omitted the best fit straight line will be found.
TREND returns an array of the y values of the straight line found, corresponding to the x values in new_xvalues (or if omitted xvalues). It must be entered as an array formula (for example by using Cntrl-Shift-Enter rather than just Enter).
yvalues and xvalues must be the same size. new_xvalues may have a different size.

### Example:

=TREND(B2:B5; A2:A5; A2:A7)

when entered as an array formula in cell C2, where the x values in A2:A7 are 1,2,3,4,5, 6 and the y values in B2:B4 are 2, 4, 6.1, 8 returns {2.01|4.02|6.03|8.04|10.05|12.06}. The data points are very nearly on the line y = 2x (and would be if B4 contained 6 instead of 6.1). The best fit line found is therefore very nearly y=2x.
This example shows how TREND may be used to predict future values.