Answer Key

z scores and Percentiles Comprehensive Practice

answer key

1. a. Joe was (79 – 74)/6 = 0.83 standard deviations above the mean in Chemistry. Joe was (71 – 60)/8 = 1.4 standard deviations above the mean in English.

b. He did better in English. His performance was further above the mean compared to the other students in the class.

2. 10.7%

3. 89%

4. 78.5%

5. -1.28

6. 1.28

7. -1.645, +1.645

8. a. 14%

b. 33%

c. 24.5%

d. 47.42 inches