Chapter 8 provides knowledge of sampling methods and central limit theorem. When you have completed this chapter, you will be able to: Explain under what conditions sampling is the proper way to learn something about a population, describe methods for selecting a sample, define and construct a sampling distribution of the sample mean,. | l Chapter 8 p g n i m a S Methods & Central Limit Theorem When you have completed this chapter, you will be able to: Chapter Goals Describe methods for selecting a sample. Define and construct a sampling distribution of the sample mean. 1. 2. 3. Explain under what conditions sampling is the proper way to learn something about a population. Explain the central limit theorem. 4. Use the central limit theorem to find probabilities of selecting possible sample means from a specified population. 5. We use sample information to make decisions or inferences about the population. Two KEY steps: Sampling Choice of a proper method for selecting sample data & 2. Proper analysis of the sample data (more later) KEY 1. Sampling Sampling KEY 1. If the proper method for selecting the sample is NOT MADE the SAMPLE will not be truly representative of the TOTAL Population! and wrong conclusions can be drawn! of the physical impossibility of checking all items in the population, and, also, it would | l Chapter 8 p g n i m a S Methods & Central Limit Theorem When you have completed this chapter, you will be able to: Chapter Goals Describe methods for selecting a sample. Define and construct a sampling distribution of the sample mean. 1. 2. 3. Explain under what conditions sampling is the proper way to learn something about a population. Explain the central limit theorem. 4. Use the central limit theorem to find probabilities of selecting possible sample means from a specified population. 5. We use sample information to make decisions or inferences about the population. Two KEY steps: Sampling Choice of a proper method for selecting sample data & 2. Proper analysis of the sample data (more later) KEY 1. Sampling Sampling KEY 1. If the proper method for selecting the sample is NOT MADE the SAMPLE will not be truly representative of the TOTAL Population! and wrong conclusions can be drawn! of the physical impossibility of checking all items in the population, and, also, it would be too time-consuming the studying of all the items in a population would NOT be cost effective the sample results are usually adequate the destructive nature of certain tests Why Sample the Population? Because Sampling with Replacement Each data unit in the population is allowed to appear in the sample more than once Each data unit in the population is allowed to appear in the sample no more than once Each data unit in the population has a known likelihood of being included in the sample Non-Probability Sampling Does not involve random selection; inclusion of an item is based on convenience Probability Sampling without Replacement Techniques Methods Simple Random Systematic Random Stratified Random Cluster Sampling .each item(person) in the population has an equal chance of being included items(people) of the population are arranged in some order. A random starting point is selected, and then every kth member of the population is selected for the sample a population is first .
