Let \( X \) be a random variable such that the probability function of a distribution is given by \( P(X = 0) = \dfrac{1}{2} , \; P(X = j) = \dfrac{1}{3^{j}} \; (j = 1, 2, 3, \ldots, \infty) \). Then the mean of the distribution and \( P(X \text{ is positive and even}) \) respectively are:
