The properties of the power function of the test of tendency or the "quadrant measure of association" are studied. A formula giving a lower bound for the exact power function of this test with respect to normal bivariate one-tailed $(\rho > 0)$ alternatives is obtained. Further, an approximate formula for this "minimum power" is suggested. Some numerical values are calculated from the exact and approximate formulae for this lower bound of the power function. A comparison with Konijn's approximation is presented.