A college is planning to finance an expansion of its student center through a special $20 annual fee to be levied on each student for the next 4 years. Because the project will take 2 years to complete, the students who are currently juniors or seniors will not benefit from the expansion. The campus newspaper wants to conduct a poll to seek the opinions of students on this expansion. Such opinions of students are likely to depend on their current class status, so the newspaper decides to use a stratified random sample with four class levels (freshmen, sophomores, juniors, seniors) as strata. The current student body consists of 4000 freshmen, 3200 sophomores, 2800 juniors, and 2000 seniors. The sample will contain a total of 300 students, and the size of the sample from each stratum is to be proportional to the size of the subpopulation in each stratum.
a. How many freshmen should be in the sample?
b. How many students should be chosen from each of the other three class levels?