4.37 A public interest group hires students to solicit donations by telephone. After a brief training period students make calls to potential donors and are paid on a commission basis. Experience indicates that early on, these students tend to have only modest success and that 70% of them give up their jobs in their first two weeks of employment. The group hires 6 students, which can be viewed as a random sample.

a. What is the probability that at least 2 of the 6 will give up in the first two weeks?

b. What is the probability that at least 2 of the 6 will not give up in the first two weeks?