9.50 Brain exercises and a paired-samples t test: PowerBrainRx, a Hong Kong–based for-profit company, promises to improve cognition. Its Web site lists testimonials, including one from a parent whose children “seemed to have better working memories, improved problem-solving ability like mathematics, more logical thinking, and better academic performance” following mental exercise training. There are numerous ads for companies like PowerBrainRx on the Internet and on late-night television, but there does not seem to be a lot of research examining the specific programs these companies are selling. How could you design a study for PowerBrainRx that would use a paired-samples t test to analyze the data?