Question: A study involving ten people wants to compare the effectiveness of two different brands of antihistamines with regard to enhancing sleep. Each person is randomly assigned to take Antihistamine A on one night and Antihistamine B on the other night. With each person, the hours of sleep were recorded for each night. Explain whether each of the following terms applies to this study.

a. observational study

b. randomized experiment

c. carry-over effect (confounding)

d. matched pairs (dependent samples)

e. explanatory variable (What is it?)

f. response variable (What is it?)