This z-test calculator is very similar to the z-test function on the TI 84 calculator for conducting hypothesis tests when the population standard deviation is known. In addition to calculating the p-value and z-score of the test statistic, this calculator will also ask for a level of significance and provide a conclusion and analysis. The analysis will also explain which type of error, type I or type II, is possible and interpret what that error means. To get started, enter the population mean, population standard deviation, sample mean, sample size, direction, and level of significance.