2. Is diet or exercise effective in combating insomnia? Some believe that cutting out desserts can help alleviate the problem, while others recommend exercise. Forty volunteers suffering from insomnia agreed to participate in a month-long test. Half were randomly assigned to a special no-desserts diet; the others continued desserts as usual. Half of the people in each of these groups were randomly assigned to an exercise program, while the others did not exercise. Those who ate no desserts and engaged in exercise showed the most improvement.

a. What are the factor(s) in the experiment?

b. What are the treatments in the experiment?

c. What are the experimental units in the experiment?

d. How would you allocate experimental units to treatments?

e. How would you ensure randomization, replication and control in the experiment?