Friday

April 18, 2014

April 18, 2014

Posted by **amelie** on Sunday, April 20, 2008 at 7:09pm.

a) If X1 and X2 are independent , find

the expected value and the variance

of Y=X1+X2, which represents one

operation-repair cycle.

b)Would you expect an operation-repair

cycle to last more than 75 hours?Why?

Work

------------------------

a) E(Y)= E(X1+X2)= EX1+EX2= 56+5=61

V(Y)= ... = 20

b) P(Y>75) = P(X1+X2 >75) =

I'm not sure where to go from here, i thought of using complement but i just got stuck.

ans: no, P(Y>75)<=0.1653

**Related Questions**

probability - The life of a certain type of device has an advertised failure of ...

Intro to Probability - Widgets are produced at a certain factory by each of ...

statistics - The duration of time it takes General Motors to build a car is ...

Statistics - A telephone company's goal is to have no more than 4 monthly line ...

business math 141 - Two machines turn out all the products in a factory, with ...

Probability - 7. The random variable X is distributed normally with a mean of 12...

Quantitative Techniques - Q No. A company is seriously considering buying one ...

math - A telephone company's goal is to have no more than 4 monthly line ...

math 141 - Three machines turn out all the products in a factory, with the first...

Stats - The distribution of lifetimes for a particular brand of lightbulbs has ...