Students will:

The class will need the following:


Work on the Classroom Activity Sheet as a wholeclass activity. Have students write their answers as a ratio only. Then challenge students to work on the TakeHome Activity Sheet in pairs. Go over their responses in class. 

Use the following threepoint rubric to evaluate students' work during this lesson:

Probability in Advertising Ask students to look at newspapers and magazines for examples of how numbers are used in advertisements. For example, it is not unusual to see something like "twothirds less fat than the other leading brand" or "four out of five dentists recommend Brand T gum for their patients who chew gum." Why do advertisers use numbers like these? What information are they trying to convey? Do students think that the numbers give accurate information about a product? Why or why not? They Said What? Ask students to look at newspapers or magazines for examples of how politicians, educators, environmentalists, or others use data such as statistics and probability. Then have them analyze the use of the information. Why did the person use data? What points were effectively made? Were the data useful? Did the data strengthen the argument? Have students provide evidence to support their ideas. 
Chance and Average (Math Matters series) Grolier Education, 1999. For a brief but clear presentation of how numbers and chance work together, this volume in the Math Matters series is ideal. Important terms are underlined and included in a short glossary. Clear drawings demonstrate the concepts along with easy experiments to try. Why Do Buses Come in Threes? The Hidden Mathematics of Everyday Life Rob Eastaway and Jeremy Wyndham. John Wiley & Sons, 1998. Set up in questionandanswer format, this book offers explanations for those questions that perplex us all, starting with "Why can't I find a fourleafed clover?" The text is illustrated with line drawings, and additional problems/questions and solutions appear in shaded boxes. If you need to know "Why am I always in traffic jams?" this is your book! 
factor Definition: Something, such as a circumstance or an influence, that contributes to the production of a result. Context: Weather is an important factor to consider when planning a picnic. outcome Definition: Something that comes out of or follows from an activity or process; consequence. Context: She flipped the coin ten times, and the outcome was five heads and five tails. percent Definition: One part in one hundred. Context: He passed the test by answering 85 percent of the questions correctly. probability Definition: Fairly convincing, though not absolutely conclusive; intrinsic or extrinsic evidence of support. Context: High moisture in the air and a dropping temperature led the meteorologist to conclude a high probability of snow. random Definition: lacking or seeming to lack a regular plan, marked by an absence of bias. Context: The judges picked the winning number at random . 
This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K12 Education: 2nd Edition and have been provided courtesy of theMidcontinent Research for Education and Learningin Aurora, Colorado. Grade level: 68 Subject area: Mathematics Standard: Understands and applies basic and advanced concepts of probability. Benchmarks: Understands the relationship between the numerical expression of a probability (e.g., fraction, percentage, odds) and the events that produce these numbers. 
Marilyn Fenichel, freelance education writer and editor. 