3. Consider the following random variables )1'1,X2,X3,X4 ~ N(0,1) and X1,X2,X3,X4 i.i.d. W~N (5,9) V1,V2~X2(4) and V1,V2 i.i.d. Assume X1, X2,X3,X4, W, V are all independent of each other. Also define _ 1 x=Z'(X1+X2 +X3 +X4) Each of the following random variables, Y, has either a normal distribution, x2 distribution, t distribution, or F distribution. For each random variable, state the name of the distribution and the value(s) of its parameter(s). Justify your answer: a) Y=X1+X2 b) r=x12+xz2 _ w53 '3 \"(7) _E d) Y_J _X_3 e) YX22 ids2