Researchers at a University decided to test the hypothesis that restaurant servers who squat to the level of their customers would receive a larger tip. In the experiment, the waiter would flip a coin to determine whether she/he would stand or squat next to the table. The waiter would record the amount of the bill and the tip and whether she/he stood or squatted.

1) discuss possible extraneous variables and how they could be controlled.

2) discuss the role of random assignment in this study.