consumer reports compared the effectiveness of an anti wrinkle cream with that of a plain moisturizer in reducing the appearance of wrinkles. the researchers enrolled 79 subjects with moderate to marked wrinkles, and instructed them to use both products, one on each side of the face, every morning for 12 weeks. the subjects didn't know which products they were using. at the end of the study, panelists examined before and after photos of the subjects to assess wrinkle appearance. the panelists did not know which product the subjects had used. which of the statements is true?