Use the following information for the question. The average travel time to work for a person living and working in Kokomo, Indiana is 17 minutes. Suppose the standard deviation of travel time to work is 4.5 minutes and the distribution of travel time is approximately normally distributed.
-Suppose that it is reported in the news that 12% of the people living and working in Kokomo feelthat their commute is too long. What is the travel time to work that separates the top 12% of peoplewith the longest travel times and the lower 88%? Round to the nearest tenth of a minute.
A) 22.3 minutes
B) 18.1 minutes
C) 26.0 minutes
D) None of these

Question

Quizplus · Accepted Answer

To find the travel time that separates the top 12%, we need to find the z-score that corresponds to the 88th percentile (since 100% - 12% = 88%). Using a standard normal distribution table, the z-score for 0.88 is approximately 1.175. Using the formula: X = μ + zσ, where μ = 17, σ = 4.5, and z = 1.175, we get X ≈ 22.3 minutes.

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