Question

Toby's Trucking Company determined that the distance traveled per truck per year is normally distributed, with a mean of 45 thousand miles and a standard deviation of 10 thousand miles. What percentage of trucks can be expected to travel either below 30 or above 65 thousand miles in a year

Answer 1

0.089557

Explanation:

Given thqt:

Mean, m = 45000

Standard = 10000

What percentage of trucks can be expected to travel either below 30 or above 65 thousand miles in a year

Below 30, 000

P(x < 30000)

Obtain the standardized score :

Z = (x - m) / s

Z = (30000 - 45000) / 10000

Z = - 15000 / 10000

Z = - 1.5

P(Z < - 1.5) = 0.066807

Above 65,000

P(x > 65000)

Obtain the standardized score :

Z = (x - m) / s

Z = (65000 - 45000) / 10000

Z = 20000 / 10000

Z = 2

P(Z > 2) = 0.02275 (Z probability calculator)

P(Z < - 1.5) + P(Z > 2)

0.066807 + 0.02275

= 0.089557