1. 3-5 6 th grade math Understanding Sampling

2. Objective To understand the use of sampling in describing group tendencies. Why? To understand the sampling is a statistical technique that is used when it is not possible or practical to get data from each member of the population being studied. It is important to understand sampling. This is because statistics and trends are often reported for groups and data sets that are drawn from studying samples.

3. California State Standards SDP 2.1: Compare different samples of a population with data from the entire population and identify a situation in which it makes sense to use a sample. SDP 2.4 : Identify data that represent sampling errors and explain why the sample (and the display) might be biased.

4. Vocabulary Population (Entire) – The entire group of people or things being considered in a statistical study. All. Grades, tests, quizzes, shoes, student, etc. Sample – A set of data that can be used to predict the results of a particular situation. A part of the population. Grades = population; Tests = sample

5. How to Find the Percent of a Sample 1) Count how many X are in the sample. This is the numerator 2) Count how many are in the sample total. This is the denominator. 3) Change the fraction to a decimal. Then change the decimal to a percent. What percent of a sample are green? 1)51 2)210 3)51 =.25 = 25% 210

6. When to Study a Population or a Sample A. You would study a sample if it would take too much time, or would destroy the data. B. You would study an (entire) population if it is not too difficult to measure or count the data. A.Bags of candy, average age of students in a high school or university, polling citizens of a city or town or state, … B.Height of students in a class, types of shoes in a boy scout meeting, people in a band or council, …

7. Try It! Identify the population. Are the statistics from a sample or entire population? 1)According to a 1994 survey, 79% of the adults in CA have completed high school. 1)Statistics are from a sample (too big of a population to ask) Studied: all adults in CA

8. Try Some More! Identify the population. Are the statistics from a sample or entire population? 2) The mean elevation of the 10 tallest mountains in CA is 14,196 ft. 1)Statistics are from the entire population (only 10 mountains and can get information from an encyclopedia) Studied: 10 tallest mountains in CA

9. Here’s Some More… Would you study the entire population or a sample? 3) To find out what percent of cars on CA highways have out-of- state license plates. 3) Would study: a sample. This is because it would be impossible to study ALL the cars on ALL the many highways in CA.

10. Objective Review To understand the use of sampling in describing group tendencies. Why? You now understand that sampling is a statistical technique that is used when it is not possible or practical to get data from each member of the population being studied. You also know that it is important to understand sampling. This is because statistics and trends are often reported for groups and data sets that are drawn from studying samples.

11. Independent Practice Complete problems 6- 10 Copy original problem first. Show all work! If time, complete Mixed Review: 11-15 If still more time, work on Accelerated Math.