Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Andy Smith is a Certified Financial Planner ...

The Standard Model explains how the basic building blocks of matter interact, governed by four fundamental forces. The theories and discoveries of thousands of physicists since the 1930s have resulted ...

Standard deviation shows how far a stock’s return is from its average return for a period, and can also determine whether a return for a certain period is an outlier. It’s useful to apply during times ...

There are two formulae for standard deviation. \(s = \sqrt {\frac{{\sum {{{(X - \bar X)}^2}} }}{{n - 1}}}\) (where n is the sample size). The second formula is a re ...

Mark Jahn is a financial writer, editor, consultant, and award-winning economist covering ETFs, stocks, cryptocurrencies, options, and more. Somer G. Anderson is CPA, doctor of accounting, and an ...