Estimates variance based on a sample.
Value1, value2, ... are 1 to 255 value arguments corresponding to a sample of a population.
- VARA assumes that its arguments are a sample of the population. If your data represents the entire population, you must compute the variance by using VARPA.
- Arguments can be the following: numbers; names, arrays, or references that contain numbers; text representations of numbers; or logical values, such as TRUE and FALSE, in a reference.
- Logical values and text representations of numbers that you type directly into the list of arguments are counted.
- Arguments that contain TRUE evaluate as 1; arguments that contain text or FALSE evaluate as 0 (zero).
- If an argument is an array or reference, only values in that array or reference are used. Empty cells and text values in the array or reference are ignored.
- Arguments that are error values or text that cannot be translated into numbers cause errors.
- If you do not want to include logical values and text representations of numbers in a reference as part of the calculation, use the VAR function.
- VARA uses the following formula:
where x is the sample mean AVERAGE(value1,value2,…) and n is the sample size.
Suppose 10 tools stamped from the same machine during a production run are collected as a random sample and measured for breaking strength.
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.
||Estimates the variance for the breaking strength (754.2666667)