thank you in advance

Ei'ixixz ..... Xn be independent random variables each having chi-square distribution with 1 degree of freedom. Let Y: X1 4- X2 +...+ X". State the distribution and corresponding parameter of the following random variable. I) R: 2x; i=5 4 ii) s:2x, i=1 :4 m r: ) E n iv) U =% v) V: 4R