Question

4. What is the difference between “z” and “t” statistics? When do we use z-table, and when do we use t-table?

Answer 1

Z statistics and t statistics are both used statistical hypothesis testing, when the sample size is less than 30 and population standard deviation is not known then we should used t-statistic, whereas when the sample size is greater than 30 and the population standard deviation is given then we should use Z statistic.

It is noted that wen the sample size increases 30 the T table value approaches Z table value.

The Z statistic is used to standardize the sample values which makes it more convenient to compare for desired result.