For Questions , Use the Following Narrative

For Questions , use the following narrative
Narrative: Test scores
Suppose that test scores on a particular exam have a mean of 77 and standard deviation of 5, and that they have a bell-shaped curve.
-{Test scores narrative} Suppose you take a single random sample of size 100 from this population, and you get a mean test score of 76.Is this something that you would have expected? Use a probability to justify your answer.