Got deodorant? A group of students wants to perform an experiment to determine

whether Brand $A$or Brand $B$deodorant lasts longer. One group member suggests the

following design: Recruit $40$student volunteers$—20$male and$20$female. Separate by

gender, because male and female bodies might respond differently to deodorant. Give all

the males Brand $A$deodorant and all the females Brand $B$. Have the principal judge how

well the deodorant is still working at the end of the school day on a $0$to $10$scale. Then

compare ratings for the two treatments.

a. Identify any flaws you see in the proposed design for this experiment.

b. Describe how you would design the experiment. Explain how your design addresses

each of the problems you identified in part (a).

We need to find out flaws in the proposed design for this experiment.

We don't know whether form of deodorant is more effective because one group has a certain sort of deodorant and the other group has a different type, and it has been proved that male and female bodies respond differently to deodorants. We also don't know how much each individual sweats, what they eat, or how active they are throughout the day, all of which can affect deodorant effectiveness.

We need to find out how to design the experiment and explain how to design addresses

each of the problems you identified in part (a).

It would be easier to determine the effect of the deodorant if the experiment was conducted as a matched pairs experiment. Because each person sweats differently and lives a different lifestyle, comparing deodorants with the same person would be more effective.