5
QuizMultiple Choice

Calculating and Interpreting z-Scores

Question 5 • DRHS GA-Statistical Reasoning

A popular restaurant advertises that it delivers its orders within 30 minutes. Suppose the average delivery time for one restaurant is 27 minutes with a standard deviation of three minutes. What is the delivery time with a z-score of 1.2?

Answer
A
23.4 minutes
B
27.4 minutes
C
28.2 minutes
D
30.6 minutes

Explanation

Use the z-score formula in reverse: delivery time = mean + (z-score × standard deviation). Substituting the values gives 27 + (1.2 × 3) = 30.6 minutes, so the delivery time is 30.6 minutes.

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