Hello,

For this, you have to remember that the mean is a linear function, that is to say E(aX+bY)=aE(X)+bE(Y)

For the variance, the formula is : var(aX+bY)=a^2 var(X)+b^2 var(Y), assuming that X and Y are independent. Otherwise you will need more information.

You can prove this formula with the definition of the variance that includes the mean :

var(X)=E(X^2)

and var(X+Y)=var(X)+var(Y) if X and Y are independent.

Edit : What is p ???