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Sampling
Sampling is the process of selecting a small number of elements from a larger defined target group of elements such that the information gathered from the small group will allow judgments to be made about the larger groups

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Census

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Basics of Sampling Theory
Population Element Defined target population Sampling unit Sampling frame
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Sources of Error
Sampling error is any type of bias that is attributable to mistakes in either drawing a sample or determining the sample size Nonsampling error is bias that occurs in a research study regardless of whether a sample or census is used, such as bias caused by measurement error, response errors, or coding errors
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Sampling Methods

Probability sampling

Nonprobability sampling

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Classification of Sampling Techniques
Sampling Techniques

Nonprobability Sampling Techniques

Probability Sampling Techniques

Convenience Sampling

Judgmental Sampling

Quota Sampling

Snowball Sampling

Simple Random Sampling
© 2007 Prentice Hall

Systematic Sampling

Stratified Sampling

Cluster Sampling

Other Sampling Techniques
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Types of Sampling Methods
Probability Simple random sampling Systematic random sampling Stratified random sampling Cluster sampling Nonprobability Convenience sampling Judgment sampling Quota sampling Snowball sampling

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Forms of Probability Sampling_1
Simple random sampling is a method of probability sampling in which every unit has an equal nonzero chance of being selected Systematic random sampling is a method of probability sampling in which the defined target population is ordered and the sample is selected according to position using a skip interval
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Steps in Drawing a Systematic Random Sample
1: Obtain a list of units that contains an acceptable frame of the target population 2: Determine the