Question: For each of the following situations, identify whether the appropriate test is a paired t-test or a two-sample t-test:

a. Sixty students were matched by initial pulse rate, with the two with the highest pulse forming a pair, and so on. Within each pair, one student was randomly chosen to drink a caffeinated beverage, while the other one drank an equivalent amount of water. Their pulse rates were measured 10 minutes later, to test whether caffeine consumption elevates pulse rates.

b. To determine whether lack of sleep increases appetite, researchers recruited 50 volunteers and randomly assigned 25 of them to sleep at least 8 hours a night and the other 25 to sleep at most 5 hours a night, for 3 days. Calorie intake was recorded for all 50 volunteers for the 3-day period.