Statistics

Statistics

Chapter 6: Statistical Sampling

The purpose of statistical sampling is to select a population or experimental group in order to test a statistical hypothesis. We will begin by looking at the process of sample selection and discuss common sampling techniques. You may wish to refer to the previous chapters as we progress through Chapter 6.

Learning Objectives

After reading Chapter 6 and completing the workbook, you should be able to:

1. Explain the 6 steps of sampling. 2. Explain the basic definitions of common terms used in sampling. 3. Define and interpret population. 4. Explain the different types of commonly used sampling techniques. 5. Explain the application of the presented sampling techniques.

Study Clues

A clear understanding of the basic statistical terms and concepts presented in Chapter 6 will help prepare you to advance in this course and learn more complex statistical calculations and specific statistical tests. You should refer back to Chapters 1 through 5 and understand all concepts presented thus far. As you study, you should pay particular attention to the common types of sampling techniques. You should be able to apply the sampling techniques to specific populations.

6.1 Steps to Take When Selecting a Sample

• Define the population or experimental group. • Specify and select what is to be tested or measured. • Determine the correct method of sampling • Determine the population size. • Test the hypothesis. • Collect the data.

Defining the population to be sampled is the most important of the steps. The population is determined by what the researcher wishes to study. A given population may include all people or items with the characteristics of interest. Studying an entire population is not very practical, so subsets are used, and these subsets then define the sample.

A sample that is selected at random holds the highest level of statistical power and yields the greatest interpretation of the data. Thus, it is important that you always strive for randomness when selecting a sample population!

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