Question: Suppose 6 out of 15 students in a grade-school class develop influenza, whereas 20% of grade-school students nationwide develop influenza.

A. What is the probability of obtaining 6 sick students if the national rate holds true?

B. Can this problem be answered by applying the normal approximation to a binomial distribution? Explain your answer.

C. Based on the probability obtained in A, would you say that your sample rate is different from the national influenza rate?

D. What is the probability of obtaining at least 6 sick students if the national rate holds true?

E. Interpret the obtained probability in problem D.