A set of 50 data values has a mean of 15 and a variance of 25. Find the standard score of a data value = 30.
Following are the American College Test (ACT) scores attained by the 25 members of a local high school graduating class:
21 24 23 17 31 19 19 20 19 25 17 23 16
21 20 28 25 25 21 14 19 17 18 28 20
Find P99, P90, and P80 for the ACT scores. [Hint: Use nk/100 to find the location in the ordered data for each percentile.]