William Sealy Gosset Invented Z Test
Z Test was Invented in 1908
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.
It is a statistical test used to determine whether two population means are different when the variances are known and the sample size is large. The test statistic is assumed to have a normal distribution, and nuisance parameters such as standard deviation should be known for an accurate z-test to be performed.
The t-statistic was introduced in 1908 by William Sealy Gosset, a chemist working for the Guinness brewery in Dublin, Ireland.