Question

see picture

Answer 1

it's combinations wit r.v. and variance

Answer 2

i keep getting 145 but that isn't right

Answer 3

check with the formulas for variance and expectation

Answer 4

I can get it down to
E[16+40E(x)+25E(x^2)]

Answer 5

and I know E(x^2) is the variance

Answer 6

so i try 40(3)+25(1)=145, but that isn't correct

Answer 7

http://en.wikipedia.org/wiki/Variance go to definition

Answer 8

So what do i do with the E(x^2)?

Answer 9

ha i got it, the 1st one is 386

Answer 10

E[x^2]=var[x]+(E(x))^2

Answer 11

and the second one is 4