Standard Deviation Helps to Determine the Variability of Some Processes

Standard deviation helps to determine the variability of some processes. Which choice explains how the standard deviation of a process would be calculated?

A) The square root of the most frequent observation occurrence in a data set.
B) The square root of the arithmetic mean value of the data set.
C) The square root of the sum of squared standard deviations about a population mean divided by the number of observations in a population.
D) The square root of the difference between the largest data range value and the smallest data value.