Question

Trucks in a delivery fleet travel a mean of 100 miles per day with a standard deviation of 29 miles per day. The mileage per day is distributed normally. Find the probability that a truck drives at least 42 miles in a day. Round your answer to four decimal places.

Answer 1

Solution :

Given that,

mean = = 100

standard deviation = =29

P (x    42 )

= 1 - P (x 42 )

= 1 - P ( x -  / ) ( 42 - 100 / 29)

= 1 - P ( z - 58 / 29 )

= 1 - P ( z - 2)

Using z table

= 1 - 0.0228

= 0.9772

Probability = 0.9772