In a study of 420,095 cell phone users in Denmark, it was found that 135 develop
ID: 3174693 • Letter: I
Question
In a study of 420,095 cell phone users in Denmark, it was found that 135 developed cancer of the brain or nervous system. If we assume that the use of cell phones has no effect on developing such cancer, then the probability of a person having such a cancer is 0.000340. Assuming that cell phones have no effect on developing cancer, find the mean for the number of people in groups of 420,095 that can be expected to have cancer of the brain or nervous system. Round to one decimal place.
Also find the standard deviation
What do these results suggest about the publicized concern that cell phones are a health danger because they increase the risk of cancer of the brain or nervous system? Fully explain your answer.
Based on your results above, is it unusual to find that among 420,095 people, there are 135 cases of cancer of the brain or nervous system?
Explanation / Answer
mean =np=420095*0.00034=142.8
std deviation =(np(1-p))1/2 =11.9
this suggest that expected number of people who are supposed to have cancer in a sample size of 420095 on an average will be 142.8 with and error of 11.9 give and take
for P(X>135) =1-P(X<135) =1-P(Z<(135-142.8)/11.9) =1-P(Z<-0.65546) =1-0.256=0.744
as probability of having 135 or above cancer cases are not unusal; hence it is not unusual to find that among 420,095 people, there are 135 cases of cancer of the brain or nervous system