According to a survey of the top 10 employers in a major city, a worker spends an average of 413 minutes a day on the job. Suppose the standard deviation is 26.8 minutes and the time spent is approximately a normal distribution.
-Within which interval will the times of approximately 68.26% of all workers fall?
A)[394.8,431.2]
B)[386.2,439.8]
C)[372.8,453.2]
D)[359.4,466.6]
E)[332.6,493.4]

Question

Quizplus · Accepted Answer

The interval that captures 68.26% of the values is one standard deviation on either side of the mean. Using the formula, mean ± (standard deviation), and the given information, we get 413 ± 26.8. This simplifies to [386.2, 439.8]. Therefore, the best choice is B.

According to a Survey of the Top 10 Employers in a Major