Z-TEST
Z -test 17 languages Article Talk Read Edit View history From Wikipedia, the free encyclopedia "Z test" redirects here. For the "Z-test" procedure in the graphics pipeline , see Z-buffering . A Z -test is any statistical test for which the distribution of the test statistic under the null hypothesis can be approximated by a normal distribution . Z-tests test the mean of a distribution. For each significance level in the confidence interval , the Z -test has a single critical value (for example, 1.96 for 5% two tailed) which makes it more convenient than the Student's t -test whose critical values are defined by the sample size (through the corresponding degrees of freedom ). Both the Z test and Student's t-test have similarities in that they both help determine the significance of a set of data. However, the z-test is rarely used in practice because the po...