Question

For the clinical trials of a weight-loss drug containing Garcinia Cambogia the subjects were randomly divided into two groups. The first received an inert pill along with an exercise and diet plan, while the second received the test medicine along with the same exercise and diet plan. The patients do not know which group they are in, nor do the fitness and nutrition advisors. a. Which is the treatment group? b. Which is the control group (if there is one)? c. Is this study blind, double-blind, or neither? d. Is this best described as an experiment, a controlled experiment, or a placebo-controlled experiment?



To test a new lie detector, two groups of subjects are given the new test. One group is asked to answer all the questions truthfully. The second group is asked to tell the truth on the first half of the questions and lie on the second half. The person administering the lie detector test does not know what group each subject is in. Does this experiment have a control group? Is it blind, double-blind, or neither? Explain.​​​​​​​

Answer 1

a. The second group which receives the test medicine along with an exercise and diet plan is the treatment group.  

b. Yes, the control group is the first group that receives an inert pill along with the same exercise and diet plan.

c. This is a double-blind study since neither the patients nor the fitness and nutrition advisors know which one is the control group and which one is the treatment group.

d. This is best described as a placebo-controlled experiment because there is a control group in this experiment that receives a placebo and another group that receives the treatment.

Yes, this experiment has a control group. It is the group that has been asked to answer all the questions truthfully.

This is a single-blind study since the experimenter administering the lie detector test does not know what group each subject is in, however, the subjects are aware of which group they are in.