9) The distribution of annual incomes of a sample of college graduates is normally distributed with a mean of $52,000 and a standard deviation of 1,000. About 68 percent of the incomes lie between what two income levels? A) 51,000 and 53,000 B) 53,000 and 57,000 C) 52,000 and 62,000 D) 50,000 and 60,000