A psychologist is studying the effect of sleep deprivation on anxiety feelings. A group of subjects is assigned at random to one of three treatments: A, no interruption of sleep; B, subject awakened from deep sleep twice during the night; and C, subject awakened from deep sleep four times during the night. This procedure was repeated for five nights and each day all subjects were given a test to determine the level of anxiety. High scores mean high anxiety. The total of the five scores is recorded:
a. Are there any differences in the anxiety scores? State Ho and test. Find the P-value.
b. Apply the method of multiple comparisons. Use a = .15.