Show that the rth moment about the origin of the gamma distribution is p p'T(a+r) I'(a) X [Hint. Substitute y = in the integral defining u', and then use the gamma function to evaluate the integral:] Extract the constants out of the integral. 8 S (y (r + a) - 1 c P'r T(a) 0 (Simplify your answer.) dy p'r(a+r) follow from this result? How does p'T(a) OA. The integral is the gamma function with argument o OB. The integral is the gamma function with argument r OC. The integral evaluates as p The integral is the gamma function with argument a +r