In September 2002, a Gallup Poll found major differences of opinion based on political affiliation over whether Congress should give President Bush authority to take military action in Iraq. Overall, about 50% of the 1010 respondents were in favor, with a margin of error of ±3%. Opinion differed greatly among Republicans, Democrats, and Independents. (See the bar graph in the next column.)
a) How large did this poll estimate the difference in support between Republicans and Democrats to be?
b) Was the margin of error for that difference equal to, greater than, or less than 3%? Explain.