There are several practical ways to calculate the mean and standard deviation. Scientific calculators typically come with a built-in program for both the mean and standard deviation.

Formula of Mean: Know to How to Calculate Median for Grouped, Ungrouped data along with solved examples, questions with solution.

Understanding STDEV Add together all the cash flows you have put in the spreadsheet to calculate a total. Divide the total by the number of historical entries to calculate the mean average cash flow.

The equation for the standard error of the mean is the sample standard deviation divided by the square root of the sample size.