Question: Sampling and Nonsampling Risk. You are conducting a research study to determine the effect of a two-week workout and diet regimen on the weight loss experienced by individuals between the ages of 30 and 35 years. Health Busters, a local fitness club, has allowed you access to some of its members for their voluntary participation. Your research study will use the following methodology:
1. Solicit participation from health club members.
2. Ask members who agree to participate to weigh themselves and self-report their weight to you at a specific time.
3. Provide members a scheduled set of workouts and dietary restrictions for the upcoming two weeks.
4. Via telephone survey, obtain the members' weights following the two-week period.
5. Based on the initial weight measurement and final weight measurement, calculate the net weight gain or loss.
Required: a. How would each of the following characteristics of the methodology affect sampling risk and nonsampling risk?
1. You solicited member participation during the early morning hours when most of the members working out were doing so before going to work that day.
2. Males constituted 85 percent of your sample.
3. The health club is located near downtown where most residents are either single or married without children.
4. Because of traffic, expensive parking, and reasonable proximity of their homes to their offices, most of the patrons walk to their offices (or, in inclement weather, take taxicabs or public transportation).
5. Because of privacy concerns, you agreed to allow participants to self-report their initial and final weight measurements.
6. Because of time constraints, you were unable to monitor participants' workouts or diets during the two-week period.
b. Suggest some improvements to the methodology described to reduce potential exposure to sampling risk and nonsampling risk.