A wallboard manufacturer is concerned with meeting industry quality standards for its product. Inspecting each sheet produced would necessitate many inspectors and add about 50 more to the cost of the wallboard. Sampling per shift would only increase the cost by 3 to 4 percent and yet be capable of detecting any sub-quality wallboard. Which type of probability sampling would you recommend the company to use?
Question 2
A manufacturer is introducing a new scientific calculator and wishes to conduct a test of its ease of use. He selects a group of University math majors for his experiment. This is an example of which type of nonprobability sampling?