Let X and Y be i.i.d.Unif(0,1),and let W=X-Y.
(a) Find the mean and variance of W , without yet deriving the PDF.
(b) Show that the distribution of W is symmetric about 0, without yet deriving the PDF.
(c) Find the PDF of W.
(d) Use the PDF of W to verify your results from (a) and (b).