In April 2012, the Gallup Poll reported that in a random sample of 1016 US adults, only 17% approve of the way Congress is handling its job.
(a) Use the poll results to estimate the proportion of all US adults who approve of the way Congress is doing its job. What is the margin of error, with 99% confidence, for this estimate?
(b) If the Gallup Poll wants the estimate to be accurate to within ±1%, with 99% confidence, how large a sample must they use?