Question: Cell phones and Brain Cancer: In a study of 420,095 cell phone users in Denmark, it was found that 135 developed brain cancer. If we assume, that such cancer is not affected by cell phones, the probability of such cancer is 0.00032.

a. Assuming that cell phones have no affect on cancer, find the mean and standard deviation for the numbers of people in groups of 420,095 that can be expected to have cancer of the brain.

b. Is it “unusual” to find that among such numbers of people there are 135 cases of brain cancer? Why or why not?

c. What do these results suggest about claims that cell phone contribute to incidents of brain cancer?