How to Calculate Population Standard Deviation Using Excel

The standard deviation is a statistic term that defines the midpoint in a set of numbers. It is the midpoint where 50 percent of the numbers fall below and 50 percent fall above. The standard deviation represents the deviation of observations about the mean or average.

There are different ways to calculate the standard deviation. One of the simplest ways is to use a Microsoft Excel spreadsheet. This how-to calculation guide is for Excel 2007 version.

Things You'll Need

• Microsoft Excel 2007

Instructions

1. Add the numbers in the first column of your Excel 2007 document. For example, add the numbers 15.4,13.2,11.1,12.5,11.3 and 13 in A2, A3, A4, A5, A6 and A7.

2. Click on the "A9" cell for this example. This is the cell where you will calculate the standard deviation. When you calculate another standard deviation, choose any cell at the bottom of the list of numbers you are using.

3. Click on the "Formulas" tab while you are in the "A9" cell. Click on "Statistical" on the drop-down menu.

4. Click "Insert Function" on the top left-hand side of the Excel spreadsheet. The "Insert Function" window will pop open.

5. Click on the drop-down menu of "Or select a category."

6. Scroll down the "Select a function" window. Choose "STDEV," which is the function of standard deviation based on the sample.

7. Click "OK." The "Functions Arguments" window will pop open. Ensure that on "Number 1" cell, A2:A7 is populated. If A2:A7 is not populated, enter A2:A7 manually. Click "OK."

8. The standard deviation has been successfully calculated in the "A9" cell. In this example, the calculated value of the standard deviation is 1.560449.

Tips & Warnings

• When standard deviation has been calculated, check twice to ensure your obtained value is correct.

• Checking twice will take less than a minute, so don't hesitate to double-check for accuracy.

References

• Statistics Alive; Wendy J. Steinberg; 2008
• Statistics; Robert S. Witte; 1980
• Statistics for People Who Think They Hate Statistics, Excel 2007 Edition; Neil J. Salkind; 2010