Astudy of 420,095 danish cell phone users found that 0.0321% 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 0.0340% for those not using cell phones. use ti-84 caculator. a) use the sample data to construct s 90% ci estimate of thr 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?

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.