A dean of a business school claims that the Graduate Management Admission Test (GMAT) scores of applicants to the school's MBA program have increased during the past 5 years. Five years ago, the mean and standard deviation of GMAT scores of MBA applicants were 560 and 50, respectively. Twenty one applications for this year's program were randomly selected and the following GMAT scores were recorded. If we assume that the distribution of GMAT scores of this year's applicants is the same as that of 5 years ago, can we conclude at the 5% significance level that the dean's claim is true?
570 597 504 603 494 560 549
535 539 637 540 625 500 545
569 577 606 584 607 606 585