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...