Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Thomas J. Brock is a CFA and CPA with more ...

The mean, also commonly known as the average, is a central measure of tendency that represents the average value in a data set. It is a crucial concept in mathematics, statistics, and data analysis, ...

According to a recent poll by Gallup.com, 59% of Americans believe that the amount they pay in income taxes is fair. The survey was based on a sample 1017 American adults. If the pollsters talked to ...

Standard Error of the Mean (SEM) is a statistical term that measures the accuracy with which a sample represents a population. In other words, it is the standard ...