Records in a three-county area show that in the last few years. Girl Scouts sold an average of 45.79 boxes of cookies per year, per girl scout. with a population standard deviation of 7.24 boxes per year. 56 randomly selected Girl Scouts from the region sold an average of 44.49 boxes this year. Scout leaders are concerned that the demand for Girl Scout cookies may have decreased. 3. Test at a 10% signicance level whether the average number of boxes of cookies sold by all Girl Scouts in the three-county area is lower than the historical average of 45.79 boxes. We conclude that the ave rage number of boxes of cookies sold by all Girl Scouts in the three-county area is l v lhe historical average. b. What lower than a in part a if the probability of a Type I error is zero? not lower than b. What will your decision be in part a if the probability of a Type | error is zero? v We reject the hypothesis. We fail to reject the hypothesis. Neither decision is valid