Last edited by Jason2009; May 7th 2009 at 01:51 AM.
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Originally Posted by Jason2009 Known a, b, c are 3 independent exponentials with E(a)=E(b)=E(c)=2.
Find the variance of Y=a(b+c).
Can someone please give me some hints?
Thanks very much. The mean is:
which you should be able to do easily (using )
Then You will need:
(use your knowlege of , and as an aide to evaluating this, you should not need to do any actual integrals that way)
What kind of the property did you use?
Originally Posted by Jason2009 Thanks ,CaptainBlack.
What kind of the property did you use? If , and are independedent RVs then their joint density:
where , and are the marginal densities of , and respectivly.
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