Recent content by Samwise_geegee

I'm just not sure how to calculate E(X/Y). Is what I wrote right?

Thanks Ray! Thank you for the hint! Does this look right? E[(x+1)2]*E[(y-1)2] =(E[X2]+2E[X]+E[1])(E[Y2]-2E[Y]+E[1]) =(Var[X]+E[X]2+2E[X]+E[1])(Var[Y]+E[Y]2-2E[Y]+E[1]) =(.5+1+2+1)(2+1+1+1)=18

Homework Statement Let x and y be discrete random variables with joint probability density function P(X,Y)= 2X-Y+1/9 for x=1,2 and y=1,2 0 Otherwise Calculate E[X/Y] Homework Equations E[XY]= ∫∫XYP(X,Y)dxdy The Attempt at a Solution I can't find a property...

Homework Statement Let x and y be independent random variables with E[x]=1, E[y]=-1, var[x]=1/2, var[y]=2 Calculate E[(x+1)2(y-1)2] Homework Equations E[x]=1=μ E[y]=-1=μ var[x]=1/2 =E[(x-μ)2] var[y]=2=E[(x-μ)2] The Attempt at a Solution Since x and y are independent...

Homework Statement For a certain random variable X, P(X≤500)=.5 and P(X>650)=.0227, find σ. Homework Equations μ=expected value=mean Variance=∫(X-μ)2fx(X)dx evaluated from -∞ to ∞ σ=√Variance The Attempt at a Solution I'm not sure what the relationships between the...

Homework Statement Let X1,X2,X3 be a random sample from a normal distribution with mean μ≠0 and variance σ2=1/24. What are the values of a and b, respectively, in order for L=aX1+4X2+bX3 to have standard normal distribution?Homework Equations σ=1/√24 Converting normal distribution to...