The FORECAST function returns the forecasted y value for a given x based on sample values using linear regression analysis.
FORECAST(x-value, y-values, x-values)
x-value: The x value for which the function should return a forecasted y value. x-value must contain a number value, date/time value, or duration value.
y-values: The collection containing the y (dependent) values. y-values must contain number values, date/time values, or duration values. All values must be of the same value type.
x-values: The collection containing the x (independent) values. x-values must contain number values, date/time values, or duration values. All values must be of the same value type.
Notes
The two collections must be of the same size.
If, for example, you had data on the driving speed of a vehicle and its fuel efficiency at each speed, fuel efficiency would be the dependent variable (y) and driving speed would be the independent variable (x).
You can use the SLOPE and INTERCEPT functions to find the equation used to calculate forecast values.
Example |
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Given the following table, where A2:E2 contain the x-values and A3:E3 contain the y-values: |
A | B | C | D | E | |
|---|---|---|---|---|---|
1 | |||||
2 | 1 | 2 | 3 | 4 | 5 |
3 | 3 | 5 | 7 | 9 | 11 |
=FORECAST(9, A3:E3, A2:E2) returns 19, the expected dependent (y) value for an x-value of 9. |