題組內容

3. (30 %) Let random variables X and Y have the joint p.d.f. $f(x, y) = cxy^3, \quad 0 < y < x < 1$

(c) Calculate \( \operatorname{E}(X), \operatorname{E}(Y), \operatorname{Var}(X), \operatorname{Var}(Y) \) and \( \operatorname{Cov}(X) \).