Cumulative Abnormal Returns The following diagram shows the cumulative abnormal returns (C...

Cumulative Abnormal Returns The following diagram shows the cumulative abnormal returns (CAR) for 386 oil exploration companies announcing oil discoveries between 1950 and 1980. Month 0 in the diagram is the announcement month. Assume that no other information is received and the stock market as a whole does not move. Is the diagram consistent with market efficiency? Why or why not?