Question: Cell phone risks. Researchers at the Washington University School of Medicine randomly placed 480 rats into one of three chambers containing radio antennas. One group was exposed to digital cell phone radio waves, the second to analog cell phone waves, and the third group to no radio waves. Two years later the rats were examined for signs of brain tumors. In June 2002 the scientists said that differences among the three groups were not statistically significant.
a) Is this a study or an experiment? Explain.
b) Explain in this context what "not statistically significant" means.
c) Comment on the fact that this research was funded by Motorola, a manufacturer of cell phones.