Question
Consider three lightbulbs each of which has a lifetime that is an independent exponential random variable with parameter λ=1. The variance of the time until all three burn out is:
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Recall that the variance of an exponential with parameter λ is 1/λ2.
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Recall that the variance of an exponential with parameter λ is 1/λ2.
Answers
Anonymous
1/3 ?
drain
11/6 why it is wrong? could anyone explain this?
Anonymous
1/9 +1/4 + 1 = 1.361111