Why do we prefer the t procedures to the z procedures for in

Why do we prefer the t procedures to the z procedures for inference about a population mean? (choose one)

z requires that you know the population standard deviation .

z requires that you can regard your data as an SRS from the population.

Solution

z requires that you know the population standard deviation .

We only use z test if the population standard dev are known & size of the sample is large. T-test will be only used if the sample size is below <30 & sample stanadrd deviation is known