You've developed a protein drink that you think cures arthritis. To test it, you find 200 volunteers (100 men and 100 women) and test them to measure the amount of discomfort they feel from their arthritis. Then you give the treatment to half of the subjects and a placebo to the others. You then test them all at regular intervals and measure their improvement. You find that the subjects who received the treatment show marked improvement. The people performing the tests are not told they're studying an arthritis medication.

Question

hockeychick23 · Answer

You excitedly report your findings in an infomercial that is seen by millions of people, and sales skyrocket. But were the test results truly useful for determining the effectiveness of the treatment? Why or why not? 

A. Can’t be determined without knowing how much improvement was measured
B. Yes, it’s a valid before-and-after design. 
C. Yes, it’s a blind-study. 
D. No there was no replication
E. No, there was no control

hockeychick23 · Answer

@kropot72 @rational

dan815 · Answer

you got any work?

hockeychick23 · Answer

based on what I've read about each definition i think that its A. can't be determined without knowing how much improvement was measured but i just wanted to make sure

dan815 · Answer

I would say there has to be more testing, I am thinking A or D

kropot72 · Answer

In this experiment the subjects do not know whether they are being given the real treatment or a placebo. Also the testers do not know that treatment for arthritis has been given. The subjects being given the treatment "show marked improvement" according to the tests. Therefore this is a valid double blind experiment, making C the correct choice.

hockeychick23 · Answer

ohhh ok thanks!!!

queelius · Answer

How much improvement, if any, did the group who received the placebo have? This is the entire point of the placebo -- the control -- group.

kropot72 · Answer

@hockeychick23 You're welcome :)

queelius · Answer

It's not a valid test without comparing it to the measured improvement in the placebo control group.

kropot72 · Answer

@queelius The subjects being given the treatment "show marked improvement" according to the tests. There is no mention of improvement in the subjects taking the placebo. All the subjects were tested at regular intervals, therefore the subjects taking the placebo were a control group.

queelius · Answer

It doesn't explicitly state that the placebo group didn't show any improvement. This is science -- leave nothing unstated. If someone were to tell me the above, I would be appropriately skeptical and ask, "How much improvement did you measure in the control group?"

queelius · Answer

In other words, you're assuming things that aren't necessarily true. And since he's on an infomercial, be especially skeptical. :)

queelius · Answer

But I agree, there was a control group. It's certainly possible that I am nitpicking, but it does seem dubious to me that no explicit mention of improvement, or lack thereof, was mentioned for the placebo group.

This smells. Of course, that may have been an accident by the person who created this exercise question.

kropot72 · Answer

@queelius You make a valid point. It is certainly possible that some improvements were found in the placebo group as a result of 'The Placebo Effect'.