This is a question about linear combinations of independent random variables.
X and Y are independent random variables.
$X$ has mean 2 and standard deviation 4.
$Y$ has mean 3 and standard deviation 2.
How would you calculate the mean and standard deviation of $X - Y$?
I know that if a set of random variables are all added by k then the mean becomes mean+k but since we are adding the numbers by different numbers, how would this work?