For Exercises 5.1 and 5.2, see page 245; for 5.3 to 5.6, see page 246; for 5.7 to 5.9, see page 250; for 5.10 and 5.11, see page 253; for 5.12 and 5.13, see pages 254–255; for 5.14, see page 256; and for 5.15 to 5.17, see page 260.

Question 5.43

5.43 A safety initiative.

This year, a “safety culture change” initiative attempts to reduce the number of accidents at the plant described in the previous exercise. There are 60 reportable accidents during the year. Suppose that the Poisson distribution of the previous exercise continues to apply.

  1. What is the distribution of the number of reportable accidents in a year?
  2. What is the probability of 60 or fewer accidents in a year? (Use software.)

Does the computed probability suggest that there is evidence that the initiative did reduce the accident rate? Explain why or why not.

5.43

(a) Poisson with (b) 0.00367. Yes, because the probability is so small, it is unlikely to have occurred by chance; the initiative seems to have reduced the accident rate.