Calculates, or predicts, a future value by using existing values. The predicted value is a y-value for a given x-value. The known values are existing x-values and y-values, and the new value is predicted by using linear regression. You can use this function to predict future sales, inventory requirements, or consumer trends.
X is the data point for which you want to predict a value.
Known_y's is the dependent array or range of data.
Known_x's is the independent array or range of data.
- If x is nonnumeric, FORECAST returns the #VALUE! error value.
- If known_y's and known_x's are empty or contain a different number of data points, FORECAST returns the #N/A error value.
- If the variance of known_x's equals zero, then FORECAST returns the #DIV/0! error value.
- The equation for FORECAST is a+bx, where:
and where x and y are the sample means AVERAGE(known_x's) and AVERAGE(known y's).
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
- Create a blank workbook or worksheet.
- Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
- Press CTRL+C.
- In the worksheet, select cell A1, and press CTRL+V.
- To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
||Predicts a value for y given an x value of 30 (10.60725)