This lesson combines media literacy skills with statistical research. Students will gain a greater understanding of how statistical samples are conducted by taking polls of specific populations. These polls will be expressed in graphs, which will be compared with the same questions asked of other populations.
Math Talk# 103: The Perils of Polling: Conducting Surveys
- suggest better sample taking methods for the two skits featured in the program.
- poll specific populations and represent the data they have come up with during their polls in a graph.
- present their groups" findings in front of the class.
- compare the various groups' graphs with each other and record their inferences about the variations and similarities in the graphs.
- make inferences about sampling methods performed by professional poll takers.
- poster sized paper to draw graphs - one per group of 3-4 students
Several days before this activity, have students record statements they hear in advertisements about people expressing preference for a product. Example: "9 out of 10 dentists prefer this toothpaste over other toothpastes." Explain to students that often sampling methods are not representative of the entire population. Discuss with the class what it means for a sample to be representative of the entire population.
Emphasize that students are to watch the following video segment and record why the mayor's poll taker and the coffee poll were not representative of the entire population. In addition, students are to make suggestions about better sampling methods which could have represented the entire population.
Segmented viewing and the pause feature will be used during this video to allow students time to react and communicate their observations. BEGIN viewing the video at the start of "The Perils of Polling". PAUSE after the mayor tells the poll taker for the second time that "Once again your sample isn't very representative of the population of all the voters." Allow students to write into their math journals or on a piece of paper a description of the problem with these sampling methods and what could have been done to correct the problem. Discuss their suggestions as a whole class.
RESUME viewing the video. PAUSE the video again after the manager of the company has written down and stated that of the 150 people he employs only 13 people voted. The last statement should be, "Exactly the case your honor. The sample was totally biased." Have students describe the problem with this coffee break sampling method and how a more representative poll could have been taken. Continue viewing the video to the end of this program.
This lesson can be complemented by an awareness lesson of how advertisers use such sample methods for their purposes. Refer to the statements students have collected before the lesson. Elicit from students how such statements could have been made without adequate representation of the entire population.
Explain to students that you would like for them to see for themselves how polling various samples can affect the outcome of a poll. Announce that each group of students will ask the same question of different population samples.
Assign each group of students a different population to poll. For example, one group may only poll adults, another group may only poll kindergardeners, another group may only poll boys of a certain age, while yet another group may only poll girls of a certain age. Each group will ask the same question. For example one such question which the entire class could ask may be: What is your favorite TV show?
Have each group ask a specific number of people. After they have done so, the groups are to organize their data and create a graph of their results. For the sake of ease of comparing the various graphs all the groups may choose to represent their findings with the same type of graph.
Upon completing their graphs, each group is to present their findings in front of the class. After each group has presented their findings, display the various graphs in a prominent place, and elicit comparison statements from the students. Record what differences and similarities they have observed in the various graphs. Discuss why such differences as well as similarities may be possible, and if they think that the various populations are representative of the entire community or our entire country.
Report your classes' findings to the local newspaper for the national networks using the Internet.
Have students pose the same question to a specific number of people in their community. Emphasize that their poll should be representative of the entire population.
Have students take another poll that intentionally represents just a small fraction of the population. Then, have them create a commercial which uses these findings to its advantage.