# Microsoft KB Archive/101466

## XL: Formula to Calculate the Standard Error of the Mean

The information in this article applies to:

• Microsoft Excel for Windows, versions 3.0, 3.0a, 4.0, 5.0, 5.0c
• Microsoft Excel for OS/2, version 3.0
• Microsoft Excel for the Macintosh, versions 3.0, 4.0, 5.0, 5.0a
• Microsoft Excel for Windows 95, versions 7.0, 7.0a
• Microsoft Excel 97 for Windows
• Microsoft Excel 98 Macintosh Edition

## SUMMARY

Although the Descriptive Statistics tool in the Analysis ToolPak can generate a report that includes the standard error of the mean, there is no function in Microsoft Excel to automatically calculate this value by itself.

## MORE INFORMATION

To calculate the standard error of the mean by itself, use the one of the following formulas

= STANDARD DEVIATION / SQUARE ROOT OF THE POPULATION SIZE

-or-

= STDEV(range of values)/SQRT(number)

where:

• The "range of values" is the data used to determine the Standard Deviation.

-and-

• The "number" is the size of all the possible random samples.