A public interest group in Belgium hires students to solicit donations by telephone. After a brief training period, the students call potential donors and are paid on a commission basis. Experience indicates that these students tend to have only modest success early on and that 85% of them quit the job within the first two weeks of employment. The group hires 7 students, which can be viewed as a random sample.
a. What is the probability that at least 2 of the 7 will give up in the first two weeks?
b. What is the probability that at least 2 of the 7 will not give up in the first two weeks?