Expert Answers

1- For the following studies describe the population, sample, population parameters, and sample statistics.
A- An AP/CBS telephone poll of 998 randomly selected Americans revealed that 6 in 10 people believe there has been progress in finding a cure for cancer in the last 30 years.
B- A Gallup poll of 1051 American adults shows that 32% of Americans say they have been spending less in recent months and 27% say they are saving more now and intend to make this their new, normal pattern in the years ahead.

2- Identify the sampling method (simple random sampling, systematic sampling) in the following studies.
A- An IRS (Internal Revenue Service) auditor randomly selects for audits 30 taxpayers in each of the filing status categories:single, head of household, married filing jointly, and married filing separately.
B- Every 100th computer chip that is produced is given a reliability test.
C- A taste test for chips and salsa is conducted at the entrance to a supermarket.

3- Determine whether the following studies are observational studies or experiments. If the study is an experiment, identify the control and treatment groups, and discuss whether single- or double-blinding is necessary. If the study is observational, state whether it is a case-control study, and if so, identify the cases and controls.
A-A breast cancer study began by asking 25,624 women questions about how they spent their leisure time. The health of these women was tracked over the next 15 years. Those women who said they exercised regularly were found to have lower incidence of breast cancer ( New England Journal of Medicine)
B- A double-blind drug versus placebo study of 103 patients suffering from tinnitus ( the perception of ringing in the ears) demonstrated the effectiveness of ginkgo biloba extract. The ginkgo treatment improved the condition of all the tinnitus patients (Annals of Otology, Rhinology, and Laryngology)