Math: Still an element of polls

A Gallup headline announcing a new poll says Nader's candidacy hurts Kerry.

Let's just call this a pop quiz on margin of error. You can e-mail your answers.

1. If Kerry drops from 50 points to 47 points, how significant is that with a margin of error of plus or minus 3 percentage points?

OK, pencils down!

While we're back on the subject, I noticed that AP's director of polling, Mike Mokrzycki, left a comment a couple of days after I posted "A day's not complete without polling news." He gives some context for the possible changes on AP's rounding policy.