In: Statistics and Probability
For each of the following functions, does a constant c > 0 exist such that the function is a joint probability density function?
If yes, what is c? If not, why not?
Part (a) gives 2 points, parts (b)–(d) give each one point.
(a) f(x, y) = ( cxye −x−2y if x ≥ 0 and y ≥ 0, 0 otherwise.
(b) f(x, y) = ( cxye −x−2y if x ≥ −1 and y ≥ 1, 0 otherwise.
(c) f(x, y) = ( e −cxy if x ≥ 0 and y ≥ 1, 0 otherwise.
(d) f(x, y) = ( 1 y e −cxy if x ≥ 0 and y ≥ 1, 0 otherwise.