When you have the average production of three machines, it is easy to calculate the average or mean production. You just add up the three means and divide by three. But what if I want the average ...

Standard deviation measures how far numbers in a data set are spread out from an average value. In investing, it is used as a measurement of portfolio volatility.

2. Find the daily standard deviation. Now, you will use the STDEV.S function in Excel. Place your cursor in D13 and type '=STDEV.S(D4:D12)' without the quotation marks. This formula calculates the ...