let x be a random variable with E(x)=1 and e[x(x-1)]=4. find var(x)

The Answer to the Question
is below this banner.

Can't find a solution anywhere?

NEED A FAST ANSWER TO ANY QUESTION OR ASSIGNMENT?

You will get a detailed answer to your question or assignment in the shortest time possible.

Here's the Solution to this Question

We are given that,

$E(x)=1$ and $E(x(x-1))=4$

We can write $E(x(x-1))$ as,

$E(x(x-1))=E(x^2-x)=E(x^2)-E(x)=4$ , but $E(x)=1$ . So, $E(x^2)-E(x)=E(x^2)-1=4\implies E(x^2)=5$

$var(x)=E(x^2)-(E(x))^2=5-(1)^2=5-1=4$

Therefore, var(x)=4.

Get updates for similar and other helpful Answers