Formulas and Functions

FORECAST
The FORECAST function returns the forecasted y value for a given x based on sample
values using linear regression analysis.
FORECAST(x-num-date-dur, y-values, x-values)
 x-num-date-dur: The x value for which the function should return a forecasted y
value. x-num-date-dur is a number value, a date/time value, or a duration value.
 y-values: The collection containing the y (dependent) values. y-values is a collection
that can contain number, date/time, or duration values. All values must be of the
same type.
 x-values: The collection containing the x (independent) values. x-values is a
collection that can contain number, date/time, or duration values. All values must be
of the same type.
Usage Notes
All arguments must be of the same type. Â
The two arrays must be of the same size. Â
If, for example, you had data on the driving speed of a vehicle and its fuel eciency Â
at each speed, fuel eciency would be the dependent variable (y) and driving speed
would be the independent variable (x).
You can use the SLOPE and INTERCEPT functions to nd the equation used to Â
calculate forecast values.
Example
Given the following table:
=FORECAST(9, A3:F3, A2:F2) returns 19.
Related Topics
For related functions and additional information, see:
“CORREL” on page 242
“COVAR” on page 250
“INTERCEPT” on page 262
“SLOPE” on page 287
“Listing of Statistical Functions” on page 225
256 Chapter 10 Statistical Functions