What proportion of the time will it take the clean-up crew 93.0 ...

[ghost!]

What proportion of the time will it take the clean-up crew 93.0 or more hours to clean the plant?

Question 2

If we assume nothing about the shape of distribution, approximately what percentage of all such tires will last between 42,500 and 57,500 miles?

[DHRUVSHAH]

Answer to Question 1

z = (93 -80) / 6.5 = 2 . Therefore, 93.0 is 2 standard deviations above the mean. Hence, 2.5 of the time more than 93.0 hours will be required.

Answer to Question 2

According to Chebyshev's Theorem, at least 89 of all such tires will last between 42,500 and 57,500 miles (i.e., within three standard deviations of the mean).

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Gracias!

[amcvicar]

Excellent