Question

A study of 420,055 cell phone users found that 136 of them developed cancer of the brain or nervous system. Prior to this study of cell phone​ use, the rate of such cancer was found to be 0.0254​% for those not using cell phones. Complete parts​ (a) and​ (b). a. Use the sample data to construct a 90​% confidence interval estimate of the percentage of cell phone users who develop cancer of the brain or nervous system. b. Do cell phone users appear to have a rate of cancer of the brain or nervous system that is different from the rate of such cancer among those not using cell​ phones? Why or why​ not?

A. No, because 0.0254​% is not included in the confidence interval.

B. Yes, because 0.0254​% is not included in the confidence interval.

C. Yes, because 0.0254​% is included in the confidence interval.

D. No, because 0.0254​% is included in the confidence interval.

Answer 1

Since np and n (1-p) exceeds 10,we use z distribution Sample number of events Sample size: Sample proportion Level of significancee Two tailed critical value: 136 givern n= 420055 given 2X p=-= 0.0324% 0.10 given 90% confidence level 1.645 from z table Margin of error: Lower limit: 0.0278% 一 P+E= 0.0359% Upper limit: a)The confidence interval is (0.0278%,0.0369%) b)Yes because 0.0254% is not included in the confidence interval