menstrual cycle length. menstrual cycle lengths (days) in an srs of nine women are as follows: {31, 28, 26, 24, 29, 33, 24, 27, 28}. use these data to test whether mean menstrual cycle length differs significantly from a lunar month (29.5 days). assume the population values vary according to a normal distribution, use a two-sided alternative, and show all hypothesis testing steps.