A major television manufacturer has determined that its 50-inch LED televisions have a mean

service life that can be modeled by a normal distribution with a mean of six years and a standard

deviation of one-half year.


a. What probability can you assign to service lives of at least (1) five years? (2) Six years?

(3) Seven and one-half years?


b. If the manufacturer offers service contracts of four years on these televisions, what percentage

can be expected to fail from wear-out during the service period?


c. What service period would achieve an expected wear-out rate of (1) 2 percent? (2) 5 percent?