Rex gets an A in a course 80% of the time. He studies hard only for half his courses. If he does study hard for a course, he gets an A 95% of the time. Assuming that he got an A in a course, how likely is it that he studied hard in that course? If someone estimates the above to be 75%, what error are they committing? Explain. Give an example of how this bias leads to an informational inefficiency in the financial markets