ACT Scores The ACT is an exam used by colleges and universit

ACT Scores The ACT 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 21.1 and the standard deviation was 5.3. The test scores of four students selected at random are15, 22, 9, and 35. (a) find the z-scores that corresponds to each value and (b) determine whether any of the values are unusual.

Solution

The scores of 9 and 35 are extreme values and a bit unusual as they lie over 2 standard deviations away from their mean.

Hope this helps.