Design a study to compare the reaction times of the left and right hands of right-handed people using a computer mouse. Two design choices are available to you. In the first, a sample of right-handed participants is randomly divided into two groups. Reaction time with the left hand is measured in one group, and reaction time with the right hand is tested in the other group.

a. What is the second design choice available to you?

b. Under what circumstances would the second choice be the preferred choice?

c. Assume that you decide to go with the completely randomized design and that, at the end of the experiment, you aim to calculate a 95% confidence interval for the difference between the mean reaction times of left and right hands. To achieve a confidence interval of specified width, what information would you require to plan an appropriate sample size?