Researchers at the University of Houston decided to test the hypothesis that restaurant servers who squat to the level of their customers would receive a larger tip ("Effect of Server Posture on Restaurant Tipping," Journal of Applied Social Psychology [1993]: 678-685). In the experiment, the waiter would flip a coin to determine whether he would stand or squat next to the table. The waiter would record the amount of the bill and of the tip and whether he stood or squatted.

a. Describe the treatments and the response variable.

b. Discuss possible extraneous variables and how they could be controlled.

c. Discuss whether blocking would be necessary.

d. Identify possible confounding variables.

e. Discuss the role of random assignment in this experiment.