Q. 17 - The Practice of Statistics for AP

Question

Which one of the following would be a correct interpretation if you have a z-score of $+2.0$ on an exam?

(a) It means that you missed two questions on the exam.
(b) It means that you got twice as many questions correct as the average student.
(c) It means that your grade was two points higher than the mean grade on this exam.
(d) It means that your grade was in the upper $2\%$ of all grades on this exam.
(e) It means that your grade is two standard deviations above the mean for this exam.

Step-by-Step Solution

Answer

The correct answer is option (e) It means that your grade is two standard deviations above the mean for this exam.

Step 1: Given information

The z - score is $+2.0$ on an exam.

Step 2: Explanation

Given: z-score is $+2.0$.
The z-score denotes the number of standard deviations a value drops out from the mean. And, the z-score of two illustrates the grade as two standard deviations, and the mean for the given exam.
Hence, the correct option is (e)