Chapter 10 – Data Analysis and Probability 10.1 – Populations and Surveys

Population – group of people, animals or objects that you want information about Sample – small part of the population

10.1 – Populations and Surveys Example 1 A school plans to offer new food items in its cafeteria, so the staff survey 100 students at the school. Identify the population and sample for this situation.

10.1 – Populations and Surveys Unbiased sample – accurately represents a population Biased sample – overrepresents or underrepresents part of the population

10.1 – Populations and Surveys Example 2 A school cafeteria wants to know if students like the new items on its menu. Tell whether the sample chosen is likely to be biased. Survey 15 people at a local mall who seem to be high school age. Survey 150 students as they enter their first- period classes. Survey 100 students in an after school music program.

10.1 – Populations and Surveys Not only can the sample be biased, but questions can be biased. When you have samples and questions that are unbiased, you can use results to make predictions.

10.1 – Populations and Surveys Example 3 Explain why the survey may be biased. Then rewrite the question to remove the bias. Would you like to see more interesting books in the school library? Would you like to increase the short hours of the cafeteria?

10.1 – Populations and Surveys Example 4 In a survey about new food items at the school cafeteria, you survey 60 students, chosen in an unbiased way. For 18 of the students, lasagna is their favorite new item. If there are 540 students in the school, predict how many think that lasagna is their favorite new menu item.

10.1 – Populations and Surveys HOMEWORK 10.1 Practice A Worksheet