BMKT 312 Sampling 1 Study Guide

# Stratified samples can produce sample statistics that

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Unformatted text preview: Stratified samples can produce sample statistics that are more precise (i.e., smaller error). Stratification also allows the investigation of the characteristics of interest for particular subgroups. 9. The difference between a proportionate stratified sample and a disproportionate stratified sample: With a proportionate stratified sample, the number of observations in the total sample is allocated among the subgroups, or strata, in proportion to the relative number of elements in each stratum in the population. Disproportionate stratified sampling involves balancing the two criteria of strata size and variability. 10. Steps in drawing a cluster sample. 1. The parent population is divided into mutually exclusive and exhaustive subsets. 2. A random sample of the subsets is selected and, generally, all elements of those subsets are included in the sample. Sampling Steps Defining the target population A population is all cases that meet designated specifications for membership in the group Researchers must be very clear and precise in defining the target population. Example: Households in the city limits of Sacramento, California, with one or more children under the age of 18 living at home. Identifying the sampling frame A sampling frame is the list of population elements from which a sample will be drawn. Commonly used sampling frames include: (a) Customer databases; (b) Telephone directories; (c) Lists developed by data compilers. Pick a sampling technique/procedure Convenience Sample: Population elements are sampled because they are in the right place at the right time. Sometimes referred to as “accidental” sampling. Easy to conduct, but there is no way to know if sample is representative of the population (i.e., cannot statistically assess sampling error). Examples include online or television “question of the day” polls Judgment Sample: Population elements are handpicked because they are expected to serve the research purpose. The researcher may believe that they are representative of the larger population or that they can offer the information ne...
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