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?

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Definitions:

Weighted Average Cost

The total cost of goods available for sale divided by the number of goods available for sale, giving each item a weight proportional to its cost.

Cost of Equity

The return a firm theoretically pays to its equity investors, i.e., shareholders, to compensate them for the risk of investing in the company.

Pre-tax Cost

The cost of an investment or expense before the application of taxes, representing the gross expense.

Market Price

The rate at present for the purchase or sale of a service or asset.