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 ...

Standard deviation and variance are two basic mathematical concepts that have an important place in various parts of the financial sector, from accounting to economics to investing. Both measure the ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

In response to my article, Is the Stock Market Too Concentrated?, which relied upon standard-deviation calculations to assess investment risk, a reader wrote: “My problem [with your argument] is ...

Learn what active risk is and how to calculate it. Understand the methods to evaluate active risk in portfolios and explore examples of funds outperforming benchmarks.

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.