9.77 PCBs Polychlorinated biphenyls (PCBs) have been found to be dangerously high in some game birds found along the marshlands of the southeastern coast of North America. A concentration of PCBs higher than 5 parts per million (ppm) in these game birds is considered to be dangerous for human consumption. A sample of 38 game birds produced an average of 7.2 ppm with a standard deviation of 6.2 ppm. Is there sufficient evidence to indicate that the mean ppm of PCBs in the population of game birds exceeds the U.S. FDA's recommended limit of 5 ppm? Use a = 0.01.