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:
Standard Deviations. The Standard Deviation is a measure of how spread out numbers are (read that page for details on how to calculate it). When we calculate the standard deviation we find that (generally): 68% of values are within. 1 standard deviation of the mean.