The director of admissions of a top-20 MBA program is interested in studying the proportion of entering students in similar graduate business programs who have achieved a composite score on the Graduate Management Admissions Test (GMAT) in excess of 630. In particular, the admissions director believes that the proportion of students entering top-rated programs with such composite GMAT scores is higher in 2010 than it was in 2000. To test this hypothesis, he has collected random samples of MBA candidates entering his program in the fall of 2010 and in the fall of 2000.
He believes that these students’ GMAT scores are indicative of the scores earned by their peers in his program and in competitors’ programs. The GMAT scores for the randomly selected students entering in each year are listed in the file P09_11.xlsx. Test the admission director’s claim at the 5% significance level and report your findings. Does your conclusion change when the significance level is increased to 10%?