# Chapter 5: Discrete Probability Distributions

2. At a certain university, half the students enrolled in a statistics class take the course on a pass-fail basis; the other half take it for a normal grade of A,...,F.

3. Calls arrive at a customer-service toll-free number at the rate of 20 per hour. Use R to find the solutions to the following questions.

4. A manufacturer is concerned with the quality of AA batteries being delivered by a certain supplier. Recently, the average battery life has fallen below the manufacturer’s standard, and so the manufacturer has begun to test the life of the batteries from this particular supplier more closely. To do this, the quality control inspectors randomly select small samples of batteries from each shipping carton of 100. Even if 1 of the batteries fails the test, the entire box of 100 is rejected and returned to the supplier. Suppose that unbeknownst to inspectors, a carton of 100 batteries contains 15 defective batteries. Use R to answer all questions.