The U.S. Justice Department and other groups have studied possible abuse by police officers in their treatment of minorities. One study, conducted by the American Civil Liberties Union, analyzed whether African-American drivers were more likely than others in the population to be targeted by police for traffic stops. They studied the results of 262 police car stops in Philadelphia during one week. Of those, 207 of the drivers were African-American, or 79% of the total. At that time, Philadelphia’s population was 42.2% African-American.

Does the number of African-Americans stopped give strong evidence of possible bias, being higher than you’d expect if we take into account ordinary random variation?

Explain your reasoning in a report of at most 250 words.