DSTDEV and DSTDEVP are used for fetching data from Database. Note – STDEV and STDEVP are for Excel 2007 or earlier. Here, the discrepancy occurs because STDEVPA and STDEVA read TRUE as 1 and STDEV.P and STDEV.S ignore it. STDEPA – It includes text and logical symbols. It is used for a sample of the population. STDEVA – It includes text and logical symbols whereas the above 2 functions don’t include text and logical symbols. Uses the same formula shown below \sigma = \sqrtģ. How would I modify the typical standard deviation to include weights on each measurement This is the standard deviation formula I am using. I want to calculate a weighted standard deviation using the weighted values and weighted average. It returns an approximate value and is used with a large population. I have several weighted values for which I am taking a weighted average. STDEV.S – It calculates the std assuming that the sample of the population is its argument. It returns an approximate value and is used with a large population. Using Excel functions, the formula is: SQRT (SUMPRODUCT (wi (xi-xbarw)2)/ (SUM (wi) (N-1)/N)) The resulting weighted standard deviation is approximately 5.9. STDEV.P – It calculates the std assuming that the entire population is its argument. Calculate Weighted Standard Deviation in Excel Finally, calculate the weighted standard deviation by using Excel functions to create the formula from above. We can have this list of formulas using ‘=’ symbol shown belowġ. In Excel we have formulas for everything and as you might have guessed for std also. Where x represents the value, and μ is the mean of the population.