Section 11.8- Samples and Surveys

Essential Question: How can we use samples to find reliable statistical information about a population?

Think about how many TOTAL fish there are in the lake.

YouTube Video Questions

Listen carefully to the videos and complete the following questions.

1. In a random sample, each member of the population is ______to be chosen.

2. The larger the sample size, the more ______it’ll be ______of the population.

3. How is a stratified random sample different than a simple random sample?

4. The English classes in the school represent the possible ______for your sample.

5. What two types of samples do you want to avoid because they are NOT RANDOM?

Bias- when part of a population is ______or ______

Break Down of Polling Sizes

Largest / Intermediate / Smallest

Goal: Use ______polling size to generate conclusion about the ______group.

Example 1: Analyzing Sampling Methods

A poll of ______in the population is called a ______. When does the government use this type of polling?

Study Methods

  • Observational study
  • ______or observe members of a study in a way that does NOT affect the study
  • Controlled experiment
  • Divide sample into ______groups
  • Impose a treatment on one group, but not on the other
  • Similar to ______experiments
  • Survey
  • Ask ______member of a sample a set of questions

NOTE: A poorly designed study can result in unreliable statistics. You should always ANALYZE a study’s methods before making general conclusions about the population.

Example 2: Analyzing Study Methods

a. Which type of study method is described in each situation?

b. Should the sample statistics be used to make a general conclusion about the population?

D. A pharmaceutical company asks for volunteers to test a new drug to treat high blood pressure. Half of the volunteers will be given the drug, and half will be given a placebo.

Wrap-Up Activity

Answer Yes or No for each question in Survey A.

Answer Yes or No for Survey B.

Were your answers different to the questions? If so, why?

Group Work:

Complete #1, 2, 4, 5.

HW: p. 728-730 #6-11, 17-19, 21-23, 25