Question: Continuing with the example of Problem, determine the following
a. The proportion of bulbs lasting more than two years.
b. The probability that a bulb chosen at random fails in the first three months of operation.
c. The probability that a bulb that has lasted for 10 years fails in the next three months of operation.
Problem: Six thousand light bulbs light a large hotel and casino marquee. Each bulb fails completely at random, and each has an average lifetime of 3,280 hours. Assuming that the marquee stays lit continuously and bulbs that burn out are replaced immediately, how many replacements must be made each year on the average?