Question: For each of the following hypotheses, identify the independent variable and the most likely levels of that independent variable.
a. Teenagers are better at video games, on average, than are adults in their 30s.
b. Spanking children tends to lead them to be more violent.
c. Weight Watchers leads to more weight loss, on average, if you go to meetings than if you participate online.
d. Students do better in statistics, on average, if they study with other people than if they study alone.
e. Drinking caffeinated beverages with dinner tends to makes it harder to get to sleep at night.