Two clinical trials were designed to test the effectiveness

Two clinical trials were designed to test the effectiveness of laser treatment for the treatment of acne. Seaton et. al. (2003) randomly divided subjects into two groups. One group received the laser treatment whereas the other group received a sham treatment. Orringer et. al. (2004) used an alternate design in which laser treatment was applied to one side of the face, randomly chosen, and the sham treatment was applied to the other side of the face. The number of facial lesions was the respond variable.

(a) Identify the main component of experimental design that differs between the two studies.

(b) Under what circumstances would there be an advantage to using the \"divided face\" design over the completely randomized (two-sample) design.

(c) Assuming that the advantage identified in part (b) is met, can you think of a disadvantage of the \"divided face\" design?

Solution

1)

laser treatment

2)

under the number of facil lesions

3)

yes, because it depends in what area of face you are working