RMS uses the STDEV.S function that estimates standard deviation based on a sample. The standard deviation is a measure of how widely values are dispersed from the average value (the mean).
Remarks:
•STDEV.S assumes that its arguments are a sample of the population.
•The standard deviation is calculated using the "n-1" method.
x is the sample mean average (number 1, number 2,...) and n is the sample size.