﻿ STDEVA function

STDEVA function

Estimates standard deviation based on a sample. The standard deviation is a measure of how widely values are dispersed from the average value (the mean).

Syntax

STDEVA(value1,value2,...)

Value1, value2, ...     are 1 to 255 values corresponding to a sample of a population. You can also use a single array or a reference to an array instead of arguments separated by commas.

Remarks

• STDEVA assumes that its arguments are a sample of the population. If your data represents the entire population, you must compute the standard deviation using STDEVPA.

• The standard deviation is calculated using the "n-1" method.

• 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.

• 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 STDEV function.

• STDEVA 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 to copy an example

1. Create a blank workbook or worksheet.

2. Select the example in the Help topic.

Note   Do not select the row or column headers.

Selecting an example from Help

3. Press CTRL+C.

4. In the worksheet, select cell A1, and press CTRL+V.

5. 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.

 1 2 3 4 5 6 7 8 9 10 11
 A Strength 1345 1301 1368 1322 1310 1370 1318 1350 1303 1299 Formula Description (Result) =STDEVA(A2:A11) Standard deviation of breaking strength for all the tools (27.46391572)

Applies To: Excel 2007

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