7. Suppose that your left and right classmates showed up to your party, but your front and behind classmates didn't. Your first instinct is to conclude that telling people that your party is popular will decrease its attendance. Which of the following circumstances could have made your experiment go wrong and yet deliver these results? (1 point) (a) My best friends were sitting next to me at the time of my experiment, left and right. (b) I arrived late to class so I didn't decide where to sit. (e) I am shy so I don't know if the treatment was properly delivered (I don't know if they heard me). (d) My best friends were running experiments of their own.

Fig: 1