The life expectancy of computer terminals is normally distributed with a mean of 4 years and a standard deviation of 0.5 year (or 6 months).

a. What percentage of terminals will last less than 4 years?

b. What is the probability that a randomly selected terminal will last more than 5 years?

c. What percentage of terminals will last between 3 and 4.5 years?

d. If the manufacturer guarantees the terminals for 3 years (and will replace them if they malfunction), what percentage of terminals will be replaced?

a. What percentage of terminals will last less than 4 years?

b. What is the probability that a randomly selected terminal will last more than 5 years?

c. What percentage of terminals will last between 3 and 4.5 years?

d. If the manufacturer guarantees the terminals for 3 years (and will replace them if they malfunction), what percentage of terminals will be replaced?