The power has gone out in your house, and you are using a small flashlight to read your probability book. You have three batteries available to you, all of the same brand, but you can't tell which brand in the dark. The flashlight uses only one battery at a time. Use the information about the two brands of batteries from Exercise 38.15 to answer the questions below.
a. If the 3 batteries are from SaveBucks, how long do you expect to have light from your flashlight? What is the standard deviation? What distribution are you using, and what are the parameters? What important assumption do you have to make about battery lives?
b. If the 3 batteries are from LittleMoola, how long do you expect to have light from your flashlight? What is the standard deviation? What distribution are you using and what are the parameters?
c. What is the probability you will need more than 3 batteries if you use the flashlight every evening for a week because you forgot to pay your electricity bill? (Assume there are 12 hours of darkness each night and 7 nights in the week.) What distribution are you using, and what are the parameters?