Consider the following two scenarios. Which is an example of an Experiment and w
ID: 3053283 • Letter: C
Question
Consider the following two scenarios. Which is an example of an Experiment and which is an Observational Study? Scenario 1 Find 100 adults with high Blood Pressure. Randomly assign 50 of the 100 adults to receive a new BP drug/treatment and the other 50 to the existing (control) BP treatment. If randomization is done correctly, there should be an equal distribution of males/females in both groups, equal age distribution, equal social-economic status, etc (both groups should be pretty much the SAME except for the drug/treatment they receive. No patterns!). Measure BP of the 100 participants for 6-weeks FDA wants to know if the new BP drug/treatment is better than the existing drug. i.e. does the new drug cause changes in BP? Scenario 2 Find 100 women age 30 of which 50 have been smoking a pack a day for 10 years while the other 50 have been smoke free for 10 years. Measure lung capacity for each of the 100 women. We want to see whether or not smoking status is related to lung capacity.
Explanation / Answer
Scenario 1 is an Experiment! Here the independent variable of interest: effect of the new drug is in control of the researcher! He has randomly divided the 100 participants into case and control groups. Hence this is a randomized experimental study.
Scenario 2 is an Observational Study! Here the independent variable of interest is the effect of smoking and whether a participant is smoking for last 10 years or not is not in the control of the researcher. So he/she has to get people from those who smoke and those who don't and as this is not in the hand of the researcher randomization between the case and control group is not possible here. Hence this is observational study.