Does heavy cell phone use increase the incidence of brain tumors? Astudy of cell phone use among 10,000 participants found that ‘‘the 10% who used their phones most often and for the longest time had a 40% higher risk of developing some form of brain cancer than those who didn’t use a mobile phone.” Nonetheless, the results were not statistically significant. Epidemiologists Saracci and Samet write that the results ‘‘tell us that the question of whether mobile-phone use increases risks for brain cancers remains open.” Based on this study, describe whether each statement below is plausible for this population:

(a) Heavy cell phone use has no effect on developing brain cancer.

(b) Heavy cell phone use is associated with an increased risk of brain cancer.

(c) Heavy cell phone use causes an increased risk of brain cancer.