Compare the Health of first-year medical students with the health of last-year medical students

To study and compare the health of first-year medical students with the health of last-year medical students, suppose researchers surveyed 111 first-year students from the Faculty of Medicine of the University of Porto, Portugal and 125 last-year students from the same University. The students volunteered for the study, and it was offered to all of the first- and last-year students.

They were asked questions about how they rated their health on a scale of 1 to 5 , how many hours they sleep at night, and how often they have been sick in the last year. a) Is this study an observational study or an experiment? Explain your answer. b) Describe the three types of data they are collecting.

Are they quantitative or qualitative? What level of measurement is each type of data: nominal, ordinal, interval, or ratio? c) Could this sampling design be described as simple random sampling? Explain. d) Are there any possible sources of bias in this study? Explain. 5) a) Explain what sampling bias is.

Then, for each of the following (b-e) identify the sampling technique used and discuss potential sources of bias (if any). Justify your answers. b) A student finds 18 friends to participate in a psychology experiment.

c) Two hundred people, 50 from each of four weight groups: underweight, normal weight, overweight, and obese, are studied and given a health score. d) Researchers interview all pregnant women in eleven randomly selected neighborhoods in the district of Northern Ethiopia to study their level of awareness of danger signs. e) Using random digit dialing, researchers ask 987 U.S. adults whether they feel comfortable wi their current financial plans for retirement. 6) Explain what a random double-blind controlled experiment would be.