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 was the difference (pre-
debate minus post-debate) in the sample proportions of likely voters who said they will vote for this candidate?
0.064 +-0.014)
= 0.025
0.064-(-0.014)
= 0.039
0 0.064 + (-0.014) = 0.050
0.064 - (-0.014) = 0.078
N
