• Welcome! The new FreeMathHelp.com forum is live. We've moved from VB4 to Xenforo 2.1 as our underlying software. Hopefully you find the upgrade to be a positive change. Please feel free to reach out as issues arise -- things will be a little different, and minor issues will no doubt crop up.

3.5.8

kbor2259

New member
Joined
Mar 26, 2012
Messages
1
Find E(Y) of fy(y)= (3/4) 0<y<1
(1/4) 2<y<3
0 elsewhere
the < should be less than or equal to
 

tkhunny

Moderator
Staff member
Joined
Apr 12, 2005
Messages
9,708
If we get to use calculus, I'd evaluate this:

\(\displaystyle \int_{-\infty}^{\infty} y\cdot f_{Y}(y)\;dy\)

Of course, I would also check for validity by verifying:

\(\displaystyle \int_{-\infty}^{\infty} f_{Y}(y)\;dy\) = 1

Without the calculus, the geometry is not difficult.

\(\displaystyle \frac{1}{2}\cdot\frac{3}{4} + \frac{5}{2}\cdot\frac{1}{4}\)

Unique answers don't care how you find them.
 
Top