Fn key. Not to be confused with Function key. The Fn key, short form for function, is a modifier key on many keyboards, especially on laptops, used in a compact layout to combine keys which are usually kept separate. It is typically found on laptops due to their keyboard size restrictions.
For a finite set of numbers, the standard deviation is found by taking the square root of the average of the squared deviations of the values from their average value. For example, the marks of a class of eight students (that is, a population) are the following eight values:
Calculate the Sample Standard Deviation. 1  Calculate the mean or average of each data set. 2  To do this, add up all the numbers in a data set and divide by the total number of pieces of data. 3  For example, if you have found numbers in a data set, divide the sum by 4.