What is the last step in calculating standard deviation?

The last step in calculating standard deviation is to take the square root of the variance. The variance, which measures how much the data points differ from the mean, is found by averaging the squared differences from the mean. After calculating the variance—either using population data (n) or sample data (n-1)—the final step of taking the square root allows you to convert that value back into the original unit of measure, making it more interpretable and directly comparable to the data set. This step is essential because the variance itself is expressed in squared units, while standard deviation gives a measure in the same units as the original data. Therefore, this step is crucial for properly communicating the spread of the data around the mean.