Question

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, since male and female bodies might respond

differently to deodorant. Give all the males Brand A deodorant and all the females Brand B. Have each student rate 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 (a).

Short answer

(a) The flaws are it is wrongly established that men and women use different types of deodorants. Effectiveness of deodorant is effected by the amount of sweat released by individual, activity and diet etc.

(b) A matching pair design is used.

Step-by-step solution

Given Information

A group of $40$students, divided into two groups of equal individuals, males and females want to conduct experiment to find out which Brand A or B of deodorant lasts longer. How well deodorant lasts is measured on the scale of$0-10$

To determine flaws in proposed design

The flaws are:

• Men uses one brand and women used other. It wrongly established that bodies of male and females respond separately. We don't know which one is actually better.
• Also activity of each person is not known as diet, health, level of activity as it also contributes to effectiveness of deodorant.

To describe how you would design the experiment and Explain how your design addresses each of the problems you identified in (a).

The most suitable design here is matched pair design, which is a type of randomized block design. It will identify the effect of deodorant. It is useful to compare the deodorants using same person as each person has different lifestyle and he/she sweats according to the activity.