Cell Phone and Brain Cancer
In a study of 420,095 cell user in Denmark, it was found that 135 developed cancer of brain or nervous system. If we suppose that the employ of cell phones has no effect on developing such cancer, then the probability of person having such cancer is 0.000340.
a) Supposing that cell phones have no effect on developing cancer, find out the mean and standard deviation for number of people in groups of 420,095 which can be expected to have cancer of the brain or nervous system.
b) Based upon the results from part (a), it is unusual to find out that among 420,095 people, there are 135 cases of cancer of brain or nervous system? Why or why not?
c) What do these results suggests regarding the publicized concern that cell phones are a health danger because they raise the risk of cancer of the brain or nervous system?