Studies show that 24% of all students at Richardson Technical College smoke. Suppose that we are interested in the proportion of the 70 students in the lunchroom cafeteria that smokes.
(a) Is the normal approximation for the proportion p = r/n valid?
(b) What is the probability that the proportion of those in the cafeteria who smoke is at least one-third?
(c) What is the probability that the proportion of those in the cafeteria who smoke is no more than 20%?