This calculator finds variance and standard deviation for students, researchers, and anyone checking how spread out a set of numbers is.
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Enter the data values, separated as shown, then choose population if the list contains the entire group or sample if it represents part of a larger group.
First find the mean, then calculate each value's squared distance from it. Population variance = sum of squared distances / N, while sample variance = sum of squared distances / (n - 1); standard deviation = square root of variance.
For the population data 2, 4, 4, 4, 5, 5, 7, 9, the mean is 5 and the variance is 4. The population standard deviation is square root of 4, which is 2.
Use population when your data includes every member of the group you care about. Use sample when the data is only a subset used to estimate the larger group.
It means the values are relatively spread out from the mean. A low standard deviation means they cluster more closely around it.
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