SAT scores: The College Board reports that in 2009, the mean score on the math SAT was 565 and the population standard deviation was 0 = 121. A random sample of 21 students who took the test in 2010 had a mean score of 530. Following is a dotplot of the 21 scores. llll111l 353 40'.) 450 50:) 5-50 500 550 m (a) Are the assumptions for a hypothesis test satised? Explain. (b) If appropriate, perform a hypothesis test to investigate whether the mean score in 2010 differs from the mean score in 2009. Assume the population standard deviation is o = 121. What can you conclude? Use the o. = 0.05 level of significance and the critical value method