The SAT is an exam used by colleges and universities to evaluate undergraduate applicants. The test scores are normally distributed. In a recent year, the mean test score was 1498 and the standard deviation was 316. The test scores of four students selected at random are 1920, 1240, 2200, and 1390.
(a) Find the z-scores that corresponds to each value
(b) Determine whether any of the values are unusual.