The national freshman-to-sophomore retention rate has held steady at 74%. A certain college has 499 of the 585 freshman return as sophomores. Does this college have a right to brag that it has an unusually high retention rate?
a. No, because their retention rate is over 6 standard deviations above the expected rate of 74%.
b. Yes, because their retention rate is over 6 standard deviation above the expected rate of 74%.
c. Yes, because their retention rate is not more than 3 standard deviations above the expected rate of 74%.
d. No, because their retention rate is not more than 3 standard deviations above the expected rate of 74%.