The proportion of college students who graduate in four years has historically been 0.5. In a sample of 40 students from XYZ University, 24 of them graduating in four years. Find the critical value for the hypothesis test that will determine if this percentage of four year graduates is significantly larger at this university. Use a = 0.05. Multiple Choice a. 1.96 b. 0.96 c. 1.645 d. 1.685