The mean score for freshmen on an aptitude test at a certain college is 560 with a standard deviation of 40. Assume the means to be measured to any degree of accuracy. What is the probability that two groups selected at random consisting of 48 and 40 students, respectively, will diffor in the mean scores by (a) more than 15 points? (b) an amount between 1 and 7 points? Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table BEBE