March 24, 2010 Math 102 OBJECTIVE: Students will be able to determine the best method of collecting data from a population in order to predict outcomes. AIM: What does it mean to “sample a population”? Why is it important to have confidence in the way we sample? STANDARDS: 6.S.1, 7.S.9 PRIOR KNOWLEDGE: What are some sources we go to so we can collect data and information? What are some ways we use this information?

We want to know: How different groups feel toward a variety of subjects Sampling - collecting information from part of a group Population – the group of people from which a a sample is chosen

Considerations Did I choose enough people for my sample? Do the people I chose represent the whole group? Situation: Maria is going to a water park. She wants to take a a survey of people at the water park to help identify the most popular water slide. She decides to ask 20 adults and 20 children at the park’s picnic area. Is this a good sample to use? Explain.

Neutral location in the water park Asking adults and children. Therefore, a good sample to use Situation: Latrelle wants to conduct a telephone survey to find out if people think that the town should pay to build a new sports arena. Which of these would be the best sample to use? Friends from the neighborhood Members of the school’s sports teams People who attend sports events Every 10th name in the phone book

Latrelle’s sample choices and explanations: a – is not large enough, and may not represent opinions of people in other parts of town b – most members of sports teams would favor it and therefore not representative c – people who attend games would favor it and is therefore not representative of everyone d – this method is random; people who favor it are just as likely to be contacted as people who don’t favor it