Z Test T Test. Population mean is not the same as the sample mean. A z test is used when the population parameters like standard deviation are known.
Differences between z test and t test. A z test is used when the population parameters like standard deviation are known. In a z test we need to compare two given sample means.
In a z test we need to compare two given sample means.
If we have a sample size of less than 30 and do not know the population variance then we must use a t test. In a z test we need to compare two given sample means. 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. A z test is used when the population parameters like standard deviation are known.
