Microsoft Office Tutorials and References
In Depth Information
Calculating linear regression
Figure 17-4 The TREND function creates a data series that can be plotted as a line on a chart.
Figure 17-5 TREND can predict the sales figures for months 19, 20, and 21.
The FORECAST function
The FORECAST function is similar to TREND, except it returns a single point along a
line rather than returning an array that defines the line. This function takes the form
=FORECAST( x, known_y’s, known_x’s ) .
The x argument is the data point for which you want to extrapolate a value. For example,
instead of using TREND, you can use the FORECAST function to extrapolate the value in cell
C23 in Figure 17-5 by using the formula =FORECAST(21, B2:B19, A2:A19), where the x
argument refers to the 21st data point on the regression line. You can use this function if you
want to calculate any point in the future.