AP Statistics

Mr. Simon

Confidence Intervals for p in the World

Your job is to find an example of aconfidence interval for p used in an article, paper, or online. You need to explain what it is, who did it and when, why it was done, and what it found. How many people were surveyed, who was surveyed, and how? Then you need to work through the math yourself to show how it was calculated.

It needs to includethe sample size, so that you can recreate the entire confidence interval calculation. Ideally it would tell you the confidence level, but articles rarely do. If it does not, you may (almost certainly correctly) assume that they used a 95% level of confidence. Finally, if your numbers don’t match, try calculating it a second time with ; remember, that’s the largest confidence interval and so the most “conservative,” and lazy reporters sometimes use it to simplify the formulas.

You willturn in a paper (about a page total, which includes calculations + explanation) and make a small presentation to the class. It does not have to be very long (2-3 minutes). No power point is required. The paper should be typed and double spaced, but the math can be by hand (although I will appreciate if it’s done with computer!). Make sure you reference where the poll came from, but a formal bibliography is not necessary. Please attach a copy of your article to your paper.

If your math doesn’t match their math, say so in your paper and presentation.

You may work alone or with at most one partner. If you work with a partner turn in one paper for both of you.

You will have todayin class. The presentations will be Friday and/or Monday!

It will be worth ten test points per person.

Keywords: margin of error ( most important!), poll, news, survey, Americans

Examples of topics that might interest you (additional keywords): income, abortion, voting, death penalty, Coke vs. Pepsi, etc. etc.!