In: Math
Check in each case whether the given function can serve as the probability distribution of an appropriate random variable. (a) f(x) = (2 x)/4 for x = 0, 1, 2; (b) f(x) = x - 2/9 for x = 1, 2, 3, 4, 5, 6; (c) f(x) = x^2 - 6x + 9/10 for x = 1, 2, 3, 4, 5; (d) f(x) = x^2 - 6x + 8/5 for x = 1, 2, 3, 4, 5.