Logging trucks have a problem with tire failures due to blowouts, cuts and large punctures; these trucks are driven fast over very rough, temporary roads. Assume that such failures occur according to a Poisson distribution with a rate of 4 per 10,000 miles.

Q15. If a truck drives 1,000 miles in each week, what is the probability that it does not have any tire failures?

a) 0.67 b) 0.72 c) 0.58 d) 0.018

Q16. If a truck drives 1,000 miles in each week, what is the probability that it has at least two failures?

a) 0.673 b) 0.061 c) 0.589 d) 0.90

Q17. What is the expected value of the number of tire failures per a 1,000 miles drive?

a) 0.4 b) 0.2 c) 0.632 d) 4

Q18. What is the standard deviation of the number of tire failures per a 1,000 miles drive?

a) 2 b) .2 c) 0.632 d) 4