Which of the following appears to contradict the proposition that the stock market is e cient? Explain.

(a) The correlation between the stock market rate of return one week and its rate of return the following week is negative.

(b) One cannot make abnormally high return by buying stocks of companies whose actual earnings beat analysts consensus estimates and short stocks of companies whose actual earnings fall short of analysts consensus estimates.

(c) Over 20% of mutual funds under perform the market index on average.