A political candidate feels that she performed particularly well in the most recent debate against her opponent. Her campaign manager polled a random sample of 400 likely voters before the debate and a random sample of 500 likely voters after the debate. The 95% confidence interval for the true difference (post-debate minus pre-debate) in proportions of likely voters who would vote for this candidate was (–0. 014, 0. 064). What is the margin of error for this confidence interval?


StartFraction 0. 064 + (negative 0. 014) Over 2 EndFraction = 0. 025

StartFraction 0. 064 minus (negative 0. 014) Over 2 EndFraction = 0. 039

0. 064 + (–0. 014) = 0. 050

0. 064 – (–0. 014) = 0. 78