Need help on these practice exam questions for my exam. Include every detail thank you.
1. You want to ask a sample of college students the question “How much do you trust information about health that you find on the Internet – a great deal, somewhat, not much, or not at all?”. You try out this and other questions on a pilot group of 7 students chosen from your class. The class members are:
Adams, Aeffner, Barnes, Bower, Burke, Cao, Cisse, Devore, Ding, Drake, Eckstein, Fassnacht, Fullmer, Gandhi, Guo, Heaton, Huling, Kahler, Kessis, Lu, Mattos, Newberg, Paulsen, Payton, Prince, Pulak, Rabin, Roberts, Shoepf, Spagnola, Terry, Vore, Wallace, Wanner, Zhang.
Assign a number to each student (in alphabetical order) and choose a systematic sample of 7 students. Describe, step-by-step, how this sample will be selected. Then write down the names of the 7 students. (Assume that the first number you selected is 4). [4 marks]
3. The 10th Annual Health Care in Canada Survey is a survey of the Canadian public’s and health care providers’ opinions on a variety of health care issues, including quality of health care, access to health care, health and the environment, and so forth. A description of the survey follows:
The 10th edition of the Health Care in Canada Survey was conducted by POLLARA Research between October 3rd and November 8th, 2007. Results for the survey are based on telephone interviews with nationally representative samples of 1,223 members of the Canadian public, 202 doctors, 201 nurses, 202 pharmacists and 201 health managers. Public results are considered to be accurate within +/-2.8%, while the margin of error for results for doctors, nurses, pharmacists and managers is +/-6.9%.
a) Why is the accuracy greater for the public than for health care providers and managers? [2 marks]
b) Why do you think they sampled the public as well as health care providers and managers? [2 marks]
c) What sampling design was employed? What must you assume about the samples that were drawn from the public, doctors, nurses, pharmacists and health managers? [2 marks]
4. Most Canadians feel that the welfare of our environment is the most important issue in Canada today. For a Statistics project, a student wanted to see if this is also true of Greater Vancouver residents. She selected random samples of people from colleges, universities, libraries, and fitness clubs and asked each person if s/he feels that the environment is the major issue facing Canadians today. 92% said ‘yes’.
Is it appropriate to infer that about 92% of all Greater Vancouver residents feel this way also? Answer this question by identifying a type of bias in her survey and by explaining how her sample differs from the population in terms of the variable in the study. [3 marks]
7. Observational studies have suggested that daily intake of Vitamin E is associated with a lower risk of heart disease. Yet, carefully designed double-blind randomized experiments have shown that vitamin E has no effect in reducing risk of heart disease. [6 marks]
a) For each study (observational and experiment), what are the response and explanatory variables and treatments? [2 marks]
b) Outline the design of each study on a diagram [2 marks]
c) For the observational study, identify a lurking variable that may explain the association between Vitamin E intake and risk of heart disease? Explain why your answer satisfies the definition of a lurking variable. (Hint: What can you say about people who regularly take Vitamin E supplements?) [2 marks]