Smoke alarms with a UL label have been certified to last 10 years (Source: Underwriters Laboratories). Assume the lifetimes of smoke alarms with a UL label are normally distributed with mean 10.8 years and standard deviation 0.3 year. Find the probability that a randomly selected smoke alarm with a UL label will last
a. between 10 and 11 years.
b. greater than 11 years.
c. less than 10.6 years.
d. less than the certified 10 years. Why is it important that your result is so close to 0?