Pronunciation: ' z ē - ˌ test
Function: noun
Date: 1951
: any of several statistical tests that use a random variable having a z distribution to test hypotheses about the mean of a population based on a single sample or about the difference between the means of two populations based on a sample from each when the standard deviations of the populations are known or to test hypotheses about the proportion of successes in a single sample or the difference between the proportion of successes in two samples when the standard deviations are estimated from the sample data