Simmons Market Research conducted a national consumer study of 13,787 respondents. The respondents were asked to indicate the primary source of the vitamins or mineral supplements they consume. Thirty-five percent indicated a multiple formula was their choice. A subset of 20 respondents who used multiple vitamins was selected for further questioning. Half of them used a One A Day vitamin; the rest used generic brands. Of this subset, 4 were asked to fill out a more complete health survey.
a. Calculate the probability that the final selection of 4 subset members were all One A Day multiple vitamin users.
b. Compute the number of One A Day users expected to be selected.
c. Calculate the probability that fewer than half of the final selection were One A Day users.