Chapter 4.2, Problem 75E

(a)

To determine

To explain how you could use slips of paper to randomly reassign the subjects to the treatment groups.

Explanation of Solution

In the question, the researchers wants to find out that is yawning is contagious or not. Thus, we can use slips of paper to randomly reassign the subjects to the treatment groups as:

First, write "yawn" on $14$ different slips of paper and "no yawn" on $36$ different slips of paper. Now, lie the papers on a table with the numbers facing down. Then, mix the papers until you no longer know which number is where on the table. And then pick one of the slips of paper, the corresponding treatment will then be used for the subject. Then, throw away the selected slip of paper. Now, repeat till all subjects have received a treatment.

(b)

To determine

To explain what conclusion would you draw about whether yawning is contagious.

Explanation of Solution

n the question, the researchers wants to find out that is yawning is contagious or not. Now, suppose we used the method in part (a) to redo the random assignment fifty times. The Fathom dot plot given in question displays the number of subjects in the yawn seed group who yawned in each of these random assignments. Thus, we conclude that by looking at the dot plot and the method in part (a) yawning does not appear contagious because between $\text{6 and 12 of the 34}$ people yawned, which is not unusual.