A survey of 1000 adults in the US conducted in March 2011 asked ‘‘Do you favor or oppose ‘sin taxes’ on soda and junk food?” The proportion in favor of taxing these foods was 32%.
(a) Find a 95% confidence interval for the proportion of US adults favoring taxes on soda and junk food.
(b) What is the margin of error?
(c) If we want a margin of error of only 1% (with 95% confidence), what sample size is needed?