What Excel function calculates the standard deviation for a sample?

The function that calculates the standard deviation for a sample is indeed =STDEV.S(). This function is designed specifically to measure the amount of variation or dispersion in a sample set of data. When working with sample data, it’s important to use the sample standard deviation formula, which corrects for bias in the estimation of the population standard deviation. This is achieved by dividing by (n-1) instead of n, where n is the number of observations in the sample.

In contrast, =STDEV.P() would be used for calculating the standard deviation of an entire population, which does not need the correction factor since it considers all data points. The choice =VAR.S() calculates the variance of a sample, which is related but different from standard deviation. Variance is the square of the standard deviation. Lastly, =AVERAGE() determines the mean of a data set and does not provide any measure of dispersion or variability. Thus, =STDEV.S() is the appropriate function to use when you need the standard deviation from a sample of data.