Question 155182
The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. 
Over a lifetime, an average U.S. driver takes 50,000 trips.
---------------------------------------------------------------- 
(a) What is the probability of a fatal accident over a lifetime?
Prop = np = 50,000*(1/4x10^6) = 0.0125 
----------------
Explain your reasoning carefully. 
Hint: Assume independent events. 
Why might the assumption of independence be violated?
Some people have more accidents than others; not all people are equally 
accident prone.
----------------------- 

(b) Why might a driver be tempted not to use a seat belt “just on this trip”?
The probability of an accident on any given trip is low.
====================================
Cheers,
Stan H.