1.A small undergraduate college has 1,000 students, evenly distributed among the four classes: freshman, sophomore, junior and senior. A study is being designed to estimate the percentage of students in the college who own a cellular phone. It is decided to interview a sample of 100 students. One student proposes the following method for selecting the sample: Write the name of each student on a ticket, put the 1,000 tickets in a box, stir them up so they are thoroughly mixed, and then take 100 tickets at random from the box. Another student objects on the grounds that this sample is unlikely to have exactly 25 students in each of the four classes. So, a second design is proposed: Hire a team of four interviewers, one from each class, and ask each interviewer to select 25 representative students from their class.(3 pts)

a)Which method of sampling is preferred in this situation? Why?(2 pts)

b)Can you suggest a better method of sampling in order to ensure that exactly 25 student from each class are contained in the sample?(1 pt)