The paper “Effect of a Nutritional Supplement on Hair Loss in Women” (Journal of Cosmetic Dermatology [2015]: 76–82) describes an experiment to see if a dietary supplement consisting of Omega 3, Omega 6, and antioxidants could reduce hair loss in women with stage 1 hair loss. One hundred twenty women volunteered to participate in the study and were randomly assigned to either the supplement group or a control group. The women in the supplement group took the supplement for 6 months. Photos of the top of the head were taken of all the women at the beginning of the study and 6 months later at the end of the study. The two photos of each woman were evaluated by an independent expert who visually determined the change in hair density. The expert who determined the change in hair density did not know which of the women had taken the supplement. 

a. Evaluate this experimental design. Do you think this is a good design or a poor design, and why? 

b. If you were designing such a study, what, if anything, would you propose to do differently?