22 The students in Class A and in Class B take the same examination. There are 28 students in Class A and 32 students in Class B. The mean score for all the students in both classes is 72.6 The mean score for the students in Class A is 75 (a) Work out the mean score for the students in Class B.

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.