We want to investigate if people are more competitive / cooperative with people of the same gender in a public goods game. We recruited 50 random men from the athletic team and 50 random women from the philosophy class. We implemented an experimental within-subject design in which each participant first plays with a couple of the same gender and then plays with a couple of the opposite gender.

a. What are the problems with this design? Please propose corrections to this design.

b. Comment briefly on the external validity of the experiment (corrected). Come up with two ideas for subsequent study that contribute to external validity (one sentence for each idea).