For Exercises 3.17 and 3.18 see page 130; for 3.19 and 3.20, see pages 131–132; for 3.21 and 3.22, see page 134; for 3.23 and 3.24, see page 136; and for 3.25, see page 138.

Question 3.19

3.19 What is the population?

For each of the following sampling situations, identify the population as exactly as possible. That is, indicate what kind of cases the population consists of and exactly which cases fall in the population. If the information given is not sufficient, complete the description of the population in a reasonable way.

  1. Each week, the Gallup Poll questions a sample of about 1500 adult U.S. residents to determine national opinion on a wide variety of issues.
  2. The 2000 census tried to gather basic information from every household in the United States. Also, a “long form” requesting additional information was sent to a sample of about 17% of households.
  3. A machinery manufacturer purchases voltage regulators from a supplier. There are reports that variation in the output voltage of the regulators is affecting the performance of the finished products. To assess the quality of the supplier’s production, the manufacturer sends a sample of five regulators from the last shipment to a laboratory for study.

3.19

(a) The population consists of all adult U.S. residents. (b) The population consists of all households in the United States. (c) The population consists of all voltage regulators from the supplier.