An Ohio university wishes to demonstrate that car ownership is detrimental to academic achievement. A random sample of 100 students who do not own cars had a mean GPA of 2.68 with a standard deviation of 0.6, while the same size of sample who own cars had a mean GPA of 2.55 with a standard deviation of 0.7. Can the university justify that the mean GPA for non-car owners is greater than the mean GPA for car owners at a 99% confidence?
Step by step method for testing the hypothesis under 5 step approach is discussed here. Excel template for each problem is also included. This template can be used to obtain the answers of similar problems.