askvity

What is the formula for stdev in Excel?

Published in Excel Formulas 3 mins read

The formulas for calculating standard deviation in Excel depend on whether you're working with a sample or an entire population. Here's a breakdown:

  • For a Sample: =STDEV.S(number1, [number2], ...) or =STDEV(number1, [number2], ...) in older versions of Excel. Use this when your data represents a subset of a larger population.

  • For a Population: =STDEV.P(number1, [number2], ...) Use this when your data represents the entire population you're interested in.

Explanation

Excel provides two primary functions for calculating standard deviation: STDEV.S and STDEV.P. The key difference lies in their application:

  • STDEV.S (Sample Standard Deviation): This formula calculates the standard deviation based on a sample of the population. It divides by n-1 (where n is the number of values) in the calculation, providing an unbiased estimate of the population standard deviation. This is the more commonly used formula.

  • STDEV.P (Population Standard Deviation): This formula calculates the standard deviation based on the entire population. It divides by n in the calculation. Use this only when you have data for the entire population.

How to Use the Formulas

  1. Select a Cell: Click on the cell where you want the result to appear.
  2. Enter the Formula:
    • For a sample, type =STDEV.S( )
    • For a population, type =STDEV.P( )
  3. Input the Data: Inside the parentheses, enter the numbers or cell ranges containing the data. You can:
    • Type the numbers separated by commas: =STDEV.S(1,2,3,4,5)
    • Enter a cell range: =STDEV.S(A1:A10) (This calculates the standard deviation of the values in cells A1 through A10).

Examples

  • =STDEV.S(2,4,6,8,10) would calculate the sample standard deviation of the numbers 2, 4, 6, 8, and 10.
  • =STDEV.P(B1:B20) would calculate the population standard deviation of the data in cells B1 to B20.
  • =STDEV.S(A1:A5, C1:C5) would calculate the sample standard deviation using the data from cells A1 through A5 and C1 through C5.

Important Considerations

  • Blank Cells and Text: Excel ignores blank cells and text values when calculating standard deviation.
  • Choosing the Right Formula: Selecting the appropriate formula (STDEV.S vs. STDEV.P) is crucial for accurate results. Use STDEV.S most of the time.

Related Articles