Many students at Matt's school claim they think more clearly while listening to their favorite kind of music. Matt thinks music interferes with thinking clearly. To test this, he recruits 84 volunteers and randomly assigns them to two groups. The "Music" group listens to their favorite music while playing a "match the animals" memory game. The "No Music" group plays the same game in silence. Below is a dot plot and some descriptive statistics for the number of turns it took each subject to complete the game (fewer turns indicates a better performance).

1.Does this data provide convincing evidence that listening to music increases the number of turns required to finish the memory game? Support your conclusion with a complete significance test.

2.Suppose Matt allowed people to choose whether or not they were in the group that listened to music while playing the game? Give an example of a problem that might arise if the subjects were allowed to choose.