Chapter 5, Problem 37PS

J.D. Power and Associates calculates and publishes various statistics concerning car quality. The dependability score measure problem experienced during the past 12 months by owners of vehicles (2016). For these models of cars, Ford had 1.02 problem per car and Toyota had 0.93 problem per car.

Let $X$ be equal to the number of problems with a Ford.

a. What assumptions must be made in order for $X$ to be distributed as a Poisson random variable? Are these assumptions reasonable?

Making the assumptions as in $\left(\text{a}\right)$ , if you purchased a Ford in the 2016 model year, what is the probability that in the past 12 months, the car had

b. Zero Problems?

c. two or fewer problem?

d. Give an operational definition for problem. Why is the operational definition important in interpreting the initial quality score?