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:
These eight numbers have the average (mean) of 5: To calculate the population standard deviation, first find the difference of each number in the list from the mean. Then square the result of each difference: Next, find the average of these values (sum divided by the number of numbers). Last, take the square root: The answer is the population standard deviation. The formula is only true if the eight numbers we started with are the whole group. If they are only a part of the group picked at random, then we should use 7 (which is n â 1) instead of 8 (which is n) in the bottom (denominator) of the second-to-last step.