Question

Pat needs to conduct a z-test on the mean of a sample. He believes the population mean is 12 and he wants to make sure his test will have a power of at least 0.9 if the true population mean is less than 10 or greater than 14. How can he make sure his test will be adequate? He must ensure that his sample size is greater than 40 He must adjust the alpha value of the test He must divide the sum of squares by the population standard deviation to find the sample size. He must calculate the d value and find his sample size using OC curves.

Answer 1

Since the test to be applied is Normal Test, the test statistic has to be divided by population standard deviation.

Sample size can be decided based on the power of the test to be more than 0.9

The OC curve approach is also a feasible approach wherein the person can take care of the sample size and choose the best one.