The sample standard deviation is a statistic that tells you if the data is collected around the mean or is spread out. It is just the square root of the sample variance.

This equation was cut out from the IASSC Reference Document.

I don’t like how IASSC made this. It is unlikely you would be calculating a sample standard deviation if you already knew the population standard deviation. I would recommend calculating the sample variance and then square rooting it.

 

Example:

Example: Find the sample variance for the given sample.

Sample = [83, 52, 93, 30, 28, 38]

First we calculate the sample mean.

Then we calculate the sample variance.

Then we calculate the sample standard deviation.