The sample mean is the average of all the items in a sample a group of observations. If you have a small to moderate population and know all of the key values you should use the standard formula. Brought to you by Sciencing.
This is a crucial step in any type of statistical calculation even if it is a simple figure.
They will be normally distributed with variance sigma2 n. Divide the result by total number of observations n minus 1. You need to get the variable for which you want to know the mean and standard deviation into the variables box on the right as per the image above. The standard formula for sample size is.