Suppose commute times in a large city are normally distributed and that 62.50% of commuters in this city take more than 21 minutes to commute one-way. if the standard deviation of such commutes is 6.2 minutes, what is the mean commute?

Question

Mathematics

Agustin Navarro

3 August, 08:57

Suppose commute times in a large city are normally distributed and that 62.50% of commuters in this city take more than 21 minutes to commute one-way. if the standard deviation of such commutes is 6.2 minutes, what is the mean commute?

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Felicity Richard · Answer 1

If 62.5% take more than 21 minutes

37.5% take less than 21 minutes

convert. 375 to a zscore using the normal distribution chart in your book

P (.375) = z - 0.318639364

(21 - x) / 6.2 = - 0.318639364

(21 - x) = - 1.9755640568

22.9755640568 = x

mean commute is 22.98 minutes