what is mu in stats

In statistics and probability theory, the Greek letter "mu" (μ) is used to denote the population mean or expected value. For example, the expected value of the mean under the null hypothesis would be denoted by μ0 while the expected value of the alternative hypothesis will be denoted by μ1. The population mean is worked out in exactly the same way as the sample mean: add all of the scores together, and divide the result by the total number of scores. The symbol μ represents the population mean, and it is used to calculate the average score of the population on a given variable.