Suppose that, after conducting an analysis of past stock prices, you come up with the following observations. Which would appear to contradict the weak form of the efficient market hypothesis?

• The average rate of return is significantly greater than zero.

• The correlation between the return during a given week and the return during the following week is zero.

• One could have made superior returns by buying stock after a 10% rise in price and selling after a 10% fall.

• One could have made higher-than-average capital gains by holding stocks with low dividend yields.