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.
There are two versions of a matched pairs experiment.
Version A: Two very similar experimental units are paired and the two treatments are randomly assigned within each pair.
Version B: Each experimental unit receives both treatments in a random order.
The version being described in this experiment is____