It is assumed that in an n-firm single-product oligopoly without product differentiation the firms face an uncertain price function, which is considered random by the firms. At each time period each firm simultaneously maximizes its expected profit and minimizes the variance of the profit since it wants to receive as high as possible profit with the least possible uncertainty. It is assumed that the best response of each firm is obtained by the weighting method. We show the existence of a unique equilibrium, and investigate the local stability of the equilibrium.