## 35. A student believes that 20% of all students think pepperoni is their favorite pizza. He performs a test of hypothesis, H0: p = 0.2, having taken a sample of 200 students and finding that 52 think pepperoni is their favorite. He finds a p-value of 0.0338, so rejects the null at ? = 0.05. He then computes a 95% confidence interval for the true proportion and finds it is (0.199, 0.321). He is confused. 20% is in the interval! What is the difference? a. He made a mistake in one of his calculations. b. The two use different values of p in computing the standard deviation. c. He should have used the plus four confidence interval.

35. A student believes that 20% of all students think pepperoni is their favorite pizza. He performs a test of hypothesis, H0: p = 0.2, having taken a sample of 200 students and finding that 52 think pepperoni is their favorite. He finds a p-value of 0.0338, so rejects the null at ? = 0.05. He then computes a 95% confidence interval for the true proportion and finds it is (0.199, 0.321). He is confused. 20% is in the interval! What is the difference?
a. He made a mistake in one of his calculations.
b. The two use different values of p in computing the standard deviation.
c. He should have used the plus four confidence interval.