National exam scores are sometimes scaled so that the population of scores is normal with U=500, o=100. In a class of 100 freshmen, the mean score was 525. In this performance basically average, or...

National exam scores are sometimes scaled so that the population of scores is normal with U=500, o=100. In a class of 100 freshmen, the mean score was 525. In this performance basically average, or significantly different? Test a hypothesis and make a decision.
Write a non-directional null-hypothesis and alternate/research hypothesis.
What is the alpha level (rejection region)?
What is the critical value for your chosen alpha level?
Calculate the test statistic.
What is your decision? Reject or fail to reject?