Last month, 85 percent of the visitors to the Sonora Candy Factory made a purchase in the on-site candy shop after taking the factory tour. This month, a random sample of 500 such visitors showed that 435 purchased candy after the tour. The manager said, "Good, the percentage of candy-buyers has risen significantly."
(a) At α = .05, do you agree?
(b) Why is it reasonable to assume normality in this test?