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 ...

Example 1: The population from which samples are selected is {1,2,3,4,5,6}. This population has a mean of 3.5 and a standard deviation of 1.70783. The next display shows a histogram of the population.

Central Limit Theorem: A sampling distribution of the mean is approximately normally distributed if the sample size is sufficiently large. This is true no matter what the population distribution is.

The power of the W statistic for testing normality proposed by Shapiro and Wilk [3] was studied by means of a sampling experiment for samples drawn from contaminated ...