National opinion polls are normally conducted by telephone over a short time span, usually 2 or 3 days. A "Presidential Approval Poll" may state that the president's approval rating is x%, "with a margin of error ± 3%." What they usually don't say is that this is really a 95% confidence interval estimate. Can we truly be 95% confident that the true percentage for all adult Americans is within 3% of the estimate?
A. Yes.
B. No.
A. Yes.
B. No.