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:
Vice versa, variance is standard deviation squared. To calculate standard deviation from variance, only take the square root. In our example, the variance was 200, therefore standard deviation is 14.14. For calculating standard deviation of a data set, first calculate the variance and then find the square root.or sample variance and standard deviation, the only difference is in step 4, where we divide by the number of items less one. In our example we would divide 1,000 by 4 (5 less 1) and get the sample variance of 250. Sample standard deviation would be 15.81 (square root of 250).