3.15. [Standardizing a random variable with a triangular pdf] Suppose X has the pdf shown: forr} (a) Find the constant c. (b) Let X denote the standardized version of X. Thus, f : X3\" for some constants C: and b so that. X has mean zero and variance one. Carefully sketch the pdf of X. Be sure to indicate both the horizontal and vertical scales of your sketch by labeling at. least one nonzero point on each of the axes. (Hint: VarX} = .)