VARA function
This article describes the formula syntax and usage of the VARAfunction in Microsoft Excel.
Description
Estimates variance based on a sample.
Syntax
VARA(value1, [value2], ...)
The VARA function syntax has the following arguments:

Value1, value2, ... Value1 is required, subsequent values are optional. 1 to 255 value arguments corresponding to a sample of a population.
Remarks

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.
Example
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 do I copy an example?

Select the example in this article. If you are copying the example in Excel Web App, copy and paste one cell at a time.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

Create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Web App, repeat copying and pasting for each cell in the example.
Important For the example to work properly, you must paste it into cell A1 of the worksheet.

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.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.


Note The value of the result depends on the number of decimal places that are used in the number format of the cell that contains the formula.