In: Statistics and Probability
Suppose the lifetime of a certain model of car battery is
assumed
to follow an exponential distribution with a mean lifetime of
5
years.
a. What is the probability that the total lifetime of the
5 batteries will exceed 9.85 years?
b. How many car batteries would be needed to be 90% sure that
the total lifetime would exceed 25 years? c. For a sample of size n
= 5, put into service at the same time
1) What is the probability the first failure occurs before
2 years?
2) What is the probability the time between the first and
second failure is less than 2 years?
3) What is the expected time of the last failure?