In a recent year, the ACT scores for the reading portion of the test were normally distributed,

Question:

In a recent year, the ACT scores for the reading portion of the test were normally distributed, with a mean of 21.3 and a standard deviation of 6.2. Find the probability that a randomly selected high school student who took the reading portion of the ACT has a score that is
(a) Less than 15,
(b) Between 18 and 25,
(c) More than 34,
(d) Identify any unusual events.
Explain your reasoning.