Before a college professor gave an exam, he held a review session, where30

of his150

students attended the review. The mean score of the students who attended was86%

, whereas the mean score of the students who didn't attend the review was79%

. The difference in the mean scores is significant at the0.05

level, assuming the review session does not associate with a higher exam score. Determine the meaning of this significance level.

Select the correct answer below:

It is not unusual to see the mean exam score of120

students be79%

because the testing abilities of students vary.

We expect the mean score of a group of30

students who attend a review session to be86%

.

At the0.05

level of significance, attendance of the review session is associated with a higher exam scor