Mean

High Quality Content by WIKIPEDIA articles! In statistics, mean has two related meanings: the arithmetic mean, the expected value of a random variable, which is also called the population mean. There are other statistical measures that use samples that some people confuse with averages - including 'median' and 'mode'. Other simple statistical analyses use measures of spread, such as range, interquartile range, or standard deviation. For a real-valued random variable X, the mean is the expectation of X. Note that not every probability distribution has a defined mean; see the Cauchy distribution for an example