A two-sample t-test is used to test if the means of two population variables are different.

Minitab's power and sample size capabilities allow you to examine how the following test properties affect each other:

·    power - the probability of being able to detect an effect of a given size.

·    sample size - the number of observations in each sample.

·    difference (effect) - the difference between m for one population and m for the other.

If you provide values (or sets of values) for any two of these properties,
Minitab will calculate the associated values for the remaining property.

By default, all calculations are based on an a-level of 0.05. However, you can select any value between 0 and 1.

A health management firm wants to know which of two hospitals, A or B, has a higher satisfaction rating among former maternity patients. The firm will use the information to refer patients, and to make suggestions for hospital improvement. The estimated standard deviation is 12.9 points.