Multiple Choice Please select the best answer and click subm

Multiple Choice: Please select the best answer and click \"submit.\" Which of the following is an example of control? Repeating a study 10 times Assigning test subjects to test groups arbitrarily Studying the effects of both therapy and no therapy on students Performing five different studies of the same drug

Solution

A control is an additional experiment you run alongside your test experiment. It is identical in every way to your test experiment, except for the one thing you are testing.

For example, say you want to know if putting an aspirin in the soil will make flowers more colorful. So you grow a group of plants, put an aspirin in the soil, and the plants produce very colorful flowers. What have you demonstrated? Nothing! Because there are dozens of reason why plants might produce very colorful flowers - materials already in the soil, temperature, light, humidity, etc. What you should have done is to grow two identical sets of plants, same seeds, same pots, same soil, same water, same light, same humidity, etc. In one set you put an aspirin in the soil. In the other set - the control set - you don\'t. Now, if the set with the aspirin have more colorful flowers than the set without the aspirin, you have demonstrated something real because the control rules out all other possible explanations for the flower color.

So, option (C) is correct because, if we study the effect of both therapy and no therapy on students, then we can test the effect of therapy.