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?

0.064+(-0.014)/2 = 0.025

0.064-(-0.014)/2 = 0.039

0.064+(-0.014) = 0.050

0.064-(-0.014) = 0.078