Suppose E(X) = 5 and E[X(X-1)] = 27.5. What is E(X2)? V(X)? The general relationship among the quantities E(X), E[X(X-1)], and V(X)?

Step-by-step explanation:

We have the following properties:

So, if we have that E[X(X-1)] = 27.5, we can write them using the first property as:

Then, replacing E(X) by 5 and solving for , we get:

Finally, using the second property and replacing by 5 and by 32.5, we get that V(X) is equal to:

h df tyjgtyj ttd y ytkgfty ty

step-by-step explanation:

tyty jry j y yj yttj yhgtyj y ghyj ytthj

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8