Question

A study of 420 comma 061 cell phone users found that 134 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 0.0327​% for those not using cell phones. Complete parts​ (a) and​ (b). a. Use the sample data to construct a 95​% confidence interval estimate of the percentage of cell phone users who develop cancer of the brain or nervous system. nothing​%less thanpless than nothing​% ​(Round to three decimal places as​ needed.)

Answer 1

Sample proportion = 134 / 420061 = 0.000319

95% confidence interval for p is

- Z * sqrt( ( 1 - ) / n) < p < + Z * sqrt( ( 1 - ) / n)

0.000319 - 1.96 * sqrt(0.000319 * 0.999681 / 420061) < p < 0.000319 + 1.96 * sqrt(0.000319 * 0.999681 / 420061)

0.000265 < p < 0.000373

0.027% < p < 0.037%

95% CI is ( 0.027 , 0.037) %