A study of the impact of caffeine consumption on reaction time was designed to correct for the impact of subjects’ prior sleep deprivation by dividing the 24subjects into 12pairs on the basis of the average hours of sleep they had had for the previous 5 nights. That is, the two with the highest average sleep were a pair, then the two with the next highest average sleep, and so on. One randomly assigned member of each pair drank 2cups of caffeinated coffee, and the other drank 2cups of decaf. Each subject’s performance on a Page Number: 690standard reaction-time test was recorded. Which of the following is the correct check of the “Normal/Large Sample” condition for this significance test?

I. Confirm graphically that the scores of the caffeine drinkers could have come from a Normal distribution.

II. Confirm graphically that the scores of the decaf drinkers could have come from a Normal distribution.

III. Confirm graphically that the differences in scores within each pair of subjects could have come from a Normal distribution.

a. I only

b. II only

c. III only

d. I and II only

e. I, I, and III

Short Answer

Expert verified

The correct option is c.

c.) III only - Confirm graphically that the differences in scores within each pair of subjects could have come from a Normal distribution.

Step by step solution

01

Step 1 -  Given information:

We have been given that:

No. of subjects = 24

No. of pairs =12

Each pair had one member drink two cups of caffeinated coffee and the other two cups of decaf.

02

Step 2 - Explanation:

The Large Enough Sample Condition evaluates whether your sample size is adequate for the population.

A common rule of thumb for the Large Enough Sample Condition is n30, where n is your sample size.

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You can find some interesting polls online. Anyone can become part of the sample just by clicking on a response. One such poll asked, “Do you prefer watching first-run movies at a movie theater, or waiting until they are available to watch at home or on a digital device?” In all, 8896people responded, with only 12%(1118people) saying they preferred theaters. You can conclude that

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