An Industrial Statistician Wants to Determine Whether Efforts to Promote

question 53

Essay

An industrial statistician wants to determine whether efforts to promote safety have been successful. By checking the records of 250 employees, he finds that 30 of them have suffered either minor or major injuries that year. A random sample of 400 employees taken in the previous year revealed that 80 had suffered some form of injury.
a. Can the statistician infer at the 5% significance level that efforts to promote safety have been successful?
b. What is the p-value of the test?