Dr. Bally believes that people who exercise are more alert and better at paying attention than people who do not exercise. To test this belief, he randomly selects 10 people who work out in a local health club on a regular basis. As a control group, he randomly selects 10 people who are not members of any health club. To assess their ability to pay attention, he has each person take a test of "vigilance". This involves monitoring a screen for an hour. Every now and then a target appears on the screen, and the subject must indicate that they have detected the target by pressing a button. Better attention is indicated by detecting a greater number of targets.

Independent Variable? Dependent Variable?

What test do you run?

What is the alternative hypothesis?