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.
-Approximately what percentage of people living and working in Kokomo have a travel time to work that is at least 20 minutes? Round to the nearest whole percent.
A)15%
B)75%
C)25%
D)None of these.

Question

Quizplus · Accepted Answer

Using the Z-score formula, Z = (X - μ) / σ, where X is 20, μ is 17, and σ is 4.5, we find Z ≈ 0.67. Looking up 0.67 in the standard normal distribution table gives approximately 0.7486, meaning 74.86% have travel times less than 20 minutes. Therefore, about 25% have travel times of at least 20 minutes.

Use the Following Information for the Question