Suppose that the lifespan of a certain model of laptop is normally distributed with mean4 years and standard deviation 4 months. Throughout this problem, use the 68-95-99.7% Rule from your notes to solve each part, with all work shown.(a) What is the probability that a laptop will last between 3 years + 4 monthsand 4 years + 8 months?(b) What is the probability that a laptop will last between 4 years and 4 years+ 8 months?(c) What is the probability that a laptop will last less than 3 years + 4 months?(d) What is the probability that a laptop will last between 4 years + 4 monthsand 5 years?(e) Suppose you and your friend bought the same exact model of laptop at thesame time, and their laptop lasted less than 3 years + 4 months after purchase, whileyours lasted longer than 4 years + 8 months. What is the probability that this wouldoccur? That is, what is the probability that one laptop chosen at random will last atmost 3 years + 4 months, while another will last more than 4 years + 8 months?Assume that laptop lifespans are independent of each other. (Again, look at the definition of independence of r.v.s)
Suppose that the lifespan of a certain model of laptop is normally distributed with mean
4 years and standard deviation 4 months. Throughout this problem, use the 68-95-
99.7% Rule from your notes to solve each part, with all work shown.
(a) What is the probability that a laptop will last between 3 years + 4 months
and 4 years + 8 months?
(b) What is the probability that a laptop will last between 4 years and 4 years
+ 8 months?
(c) What is the probability that a laptop will last less than 3 years + 4 months?
(d) What is the probability that a laptop will last between 4 years + 4 months
and 5 years?
(e) Suppose you and your friend bought the same exact model of laptop at the
same time, and their laptop lasted less than 3 years + 4 months after purchase, while
yours lasted longer than 4 years + 8 months. What is the probability that this would
occur? That is, what is the probability that one laptop chosen at random will last at
most 3 years + 4 months, while another will last more than 4 years + 8 months?
Assume that laptop lifespans are independent of each other. (Again, look at the definition of independence of r.v.s)
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