The mean operating life (MTBF) of TV picture tubes is 4,000 hours, and the failure rate of the tubes can be modeled by a negative exponential distribution. Use Table 4S.1 in your textbook (page 175) to solve these problems.
a. Determine the probability that a picture tube will fail within 3,200 hours.
b. Determine the probability that a picture tube will last at least 6,400 hours.
c. The manufacturer wishes to provide a warranty on which he will be obligated to make a replacement of 9.5% of the picture tubes sold.
For how many hours should the picture tubes be warranted?
By means cleaner models have an expected life that is exponential with a mean of four years. Find the probability that one of these cleaners will have a life that ends
After the initial four years of service.
Before four years of service are completed.
Not before six years of service.