The Excel STDEVP Function

Related Function:
STDEV Function
Standard Deviation

The Standard Deviation is a statistical measure, that is used to identify the amount that a set of values differ (or deviate) from the average value.

For any set of values, the Standard Deviation is give by the square root of the variance. I.e.

Population Standard Deviation Equation

where,

  • x takes on each value in the set;
  • x is the average (statistical mean) of the set of values;
  • n is the number of values.
For further information, see the Wikipedia Standard Deviation page
STDEVP & STDEV.P Functions

In Excel 2010, the STDEVP function has been replaced by the STDEV.P function, which has improved accuracy.

Although it has been replaced, the Stdevp function is still available in Excel 2010 (stored in the list of compatibility functions), to allow compatibility with earlier versions of Excel.

However, the Stdevp function may not be available in future versions of Excel, so it is advised that you use the STDEV.P function if possible.

Function Description

The Excel STDEVP function calculates the standard deviation of a supplied set of values.

The syntax of the function is:

STDEVP( number1, [number2], ... )

where the arguments, number1, [number2], etc, are one or more numeric values, arrays of values, or references to cells containing values.

Note that:


Stdevp Function Example

Example of use of the Excel Stdevp Function

A company keeps a record of its monthly sales figures, over the last three years. These are stored in cells B3-B14, D3-D14 and F3-F14 of the spreadsheet on the right above spreadsheet.

The standard deviation of the three years' sales figures is calculated in cell H3 of the spreadsheet. The formula for this, (shown in the spreadsheet formula bar), is:

=STDEVP( B3:B14, D3:D14, F3:F14 )

As shown in cell H3, the standard deviation for the 3 years of sales figures is calculated to be 2,484.05


Other Argument Types

In the example above, the arguments to the Stdevp function are input as 3 cell ranges. However, you can also input figures directly, as individual numbers or number arrays.

For example, if, during January and February 2010 the sales figures are 13,000 and 14,500, you could add these directly into the above function as follows:

Either as individual numbers:

=STDEVP( B3:B14, D3:D14, F3:F14, 13000, 14500 )

Or, as an array of numbers:

=STDEVP( B3:B14, D3:D14, F3:F14, {13000, 14500} )

This gives the updated standard deviation value of 2,435.35


For further information and examples of the Excel Stdevp function, see the Microsoft Office website.


Stdevp Function Errors

If you get an error from the Excel Stdevp function this is likely to be one of the following:

Common Errors
#DIV/0!-

Occurs if none of the values that are supplied to the function are numeric.

(Note that text representations of numbers, that are supplied as a part of an array, are not recognized as numeric values by the Stdevp function)
#VALUE!-Occurs if any values that are supplied directly to the Stdevp function are text values that cannot be interpreted as numbers.