A nutritionist wanted to determine which of two behaviors would give people the most energy. She selected a sample of 50 adult participants.For one month, the participants were asked to exercise for 30 minutes per day. For another month, they drank an energy drink every day. The order of the treatments were assigned to the participants at random.The participants were asked to record each day when they completed their treatment and to rate their energy level that day on a scale of 1–10.After the two months of treatments, the nutritionist collected the data and calculated and compared the mean change (exercise – energy drink) in energy level for all 50 participants.What type of experimental design did the instructor use?
Answer
A
randomized block experimental design
B
completely randomized experimental design
C
matched pairs experimental design
D
none (observational study only)
Explanation
Each participant tried both treatments: one month of daily exercise and one month of daily energy drinks. The nutritionist randomized the order and compared each person’s energy change under exercise with that same person’s change under the energy drink. Because the two measurements are paired within each participant, this is a matched pairs experimental design.
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