Standard Deviation: The usual variation from a mean (~average) in a group of numbers. The average variation from the average.
If you’re thinking there should be a simple way to calculate the standard deviation of a column in excel you’re right there is! The formula is:
=STDEV(A1,A2)
or generically:
=STDEV(cell range)
Here are some examples of how STDEV() can be used:
| A | B | C | |
| 1 | 16 | ||
| 2 | 32 | formula: | results: |
| 3 | 64 | =STDEV(A1,A2) | 11.31 |
| 4 | 256 | =STDEV(A2:A4) | 121.15 |
| 5 | =STDEV(A:A) | 111.14 |
Finding the Standard Deviation of a Cell Selection
Use the formula in cell B3 above to calculate the standard deviation on a selection of two cells. Adding more cells to you selection is easy. New cells can be added by separating any number of additional cells with a comma. E.g. =STDEV(A2,A3,A4) = 24.44. Of course if you’re using the mouse instead of editing the text directly in the formula bar you’ll just have to click on the additional cells.
Finding the Standard Deviation of a Range of Cells
Cell B4 shows how to find the standard deviation for a range of values in excel. The selection is made by clicking and dragging the mouse or entering a range of values into the formula bar separated by a colon. Multiple ranges can be added by separating each range with a comma. E.g.: =STDEV(A1:A2,C4:C5) = 32.
Finding the Standard Deviation of an Entire Column or Row
Calculating the standard deviation of an entire row is done by passing the row name to the formula, then a colon, then the row name again. E.g. =STDEV(A:A) = 111.14. The reason you must pass the same row name twice is because the second value is actually telling excel what row to stop looking at when applying the formula.
The from:to notation used by formulas when selecting rows makes it easy to use a range of rows in your formula. E.g. =STDEV(E:G). This would calculate a standard deviation of column E,F, & G.
