def MarginalBeta(self, i):
alpha0 = self.params.sum()<EOL>alpha = self.params[i]<EOL>return Beta(alpha, alpha0 - alpha)<EOL>
Computes the marginal distribution of the ith element.

        See http://en.wikipedia.org/wiki/Dirichlet_distribution
        #Marginal_distributions

        i: int

        Returns: Beta object