The lifetime of a particular brand of laptop follows a normal distribution with mean and standard deviation equal to 2.4 and 0.5 years, respectively. Assume this brand of laptop is guaranteed for 2 years,
a. What percentage of this brand of laptop is likely to be operating 3 years after purchase?
b. What percentage of this brand of laptop that would expect to fail during the guarantee period?
c. What guarantee period should the manufacturer of this laptop choose, if they want to ensure that no more than 10% of the laptops require replacement within the guarantee period?
d. What would be your answers in (a) through (c) if the standard deviation of the lifetime of this type of laptop were 1 year?