A bit of help with this problem, how to solve

[EcoEco]

Hello,

I need help with the following exercise. I don´t know how to solve it. Thanks a lot.

X=0.5Z
Y=1.2 + 0.8Z
μz=8 σz=2

E[(x-μx)·(y-μy)] ?

 

[Deleted member 4993]

Hello,

I need help with the following exercise. I don´t know how to solve it. Thanks a lot.

X=0.5Z
Y=1.2 + 0.8Z
μz=8 σz=2

E[(x-μx)·(y-μy)] ?

Do you know the definition of expected value?

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

https://www.freemathhelp.com/forum/threads/read-before-posting.109846/#post-486520​

Please share your work/thoughts about this problem.

 

[GeneralSynopsis]

Hello,

I need help with the following exercise. I don´t know how to solve it. Thanks a lot.

X=0.5Z
Y=1.2 + 0.8Z
μz=8 σz=2

E[(x-μx)·(y-μy)] ?

Ok, I'm going to rewrite this to make it more straightforward to understand.

\(Z\) is a RV with mean \(\mu_Z\) and standard deviation \(\sigma_Z\).

we have RVs: \(X=0.5\times Z\), and \(Y=1.2+0.8\times Z\)

Find the covariance of \(X\) and \(Y\) which is \(E((x-\mu_X).(y-\mu_Y))\), where \(\mu_X\) and \( \mu_Y \) are the means of \(X\) and \( Y\) respectivly.