Hypothesis Z Test Vs T Test. The mean difference between the two samples is not 0. To decide which t test to use we can apply the same rule of thumb we used for the z test.
When to use z or t statistics in significance tests. To decide which t test to use we can apply the same rule of thumb we used for the z test. If we have a sample size of less than 30 and do not know the population variance then we must use a t test.
We need to check the sample means of blood pressure of an individual before and after treatment.
Let s take an example from a blood pressure dataset. Z test is the statistical hypothesis which is used in order to determine that whether the two samples means calculated are different in case the standard deviation is available and sample is large whereas the t test is used in order to determine a how averages of different data sets differs from each other in case standard deviation or the variance is not known. 3 is quite different to the 6 of the t test. The paired sample t test is also called a dependent sample t test.
