Expert Answers

A study recruits a group of college graduates. At the time of recruitment, participants provide a blood sample that is immediately stored and they complete a questionnaire about lifestyle behaviors. The participants are followed over time to see who develops Parkinson’s Disease. Two studies are performed. Classify each study.

a) In one study, the researchers compare people reporting regular physical activity to those who are sedentary.

Case series
Case-control study
Nested case-control study
Prospective cohort study
Retrospective cohort study
Randomized clinical trial
Cross-sectional study
Ecological study
Case cohort study

b) In another study, the stored blood sample for each case is compared to the blood sample for a non-case that was alive and at risk on the day that the case was diagnosed with Parkinson’s disease. The blood samples are analyzed to see if serum levels of Vitamin D are associated with the risk of developing Parkinson’s disease.
Case series
Case-control study
Nested case-control study
Prospective cohort study
Retrospective cohort study
Randomized clinical trial
Cross-sectional study
Ecological study
Case cohort study

 

Without using the regression model, estimate the mean cry time in the following groups:

Control group infants with severe pain upon receiving the shot 

Control group infants without severe pain upon receiving the shot

Intervention group infants with severe pain upon receiving the shot

Intervention group infants without severe pain upon receiving the shot