A measure of the variation in a distribution, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean, ie. the square root of the variance.

Flickr via Google Images Standard deviation is a concept that's thrown around frequently in finance. So what is it? When working with a quantitative data set, one of the first things we want to know ...

In statistics, the average amount a number varies from the average number in a series of numbers. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.

The Journal of Educational Research is a well-known and respected periodical journal that reaches an international audience of educators and others concerned with cutting-edge theories and proposals.