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Definition
| The method used to select the sampling units. It may be classified into probability or non-probability sampling methods |
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| Sampling Error (Random Error) |
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Definition
| when a sample does not represent the population well because of chance |
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Definition
A list of sampling units from which the sample is actually selected
Example: directory, lists, rosters, patient records |
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Definition
| Making inferences about individuals based solely upon information collected at the aggregate level (e.g. organization, county, state, nation) |
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| Sampling Bias / Systematic Error |
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Definition
| A tendency to favor the selection of units that have particular characteristics |
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Definition
| Sampling design methods that ensure “all sampling units in the study population have a known, nonzero probability of being selected in the sample, typically through a random selection process”. |
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| Simple Random Sampling (SRS) |
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Definition
| every unit in a population an equal probability of being included in the sample |
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Definition
| Selects every kth element from the sampling frame after a random start |
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Definition
| breaks the population into groups or clusters, and then randomly selects a sample of clusters |
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Definition
| Population is divided into non-overlapping groups or categories, called strata, and then independent simple random samples are drawn from each stratum |
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Definition
| Sampling design methods in which “the probability of selecting any sampling unit is not known because units are selected through a nonrandom process.” |
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Definition
| Sampling elements that fit specified characteristics until a predetermined quota is reached |
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Definition
| Selects sampling elements based on expert judgment in terms of representativeness of population elements and the purposes of the study |
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Definition
| Relies on informants to identify other relevant subjects for study inclusion |
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Definition
| Relies on readily available subjects for inclusion in a sample |
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Definition
: “The probability that a significant difference will be detected if one actually exists between the populations.”
Dependent upon: Sample Size, Significance Level, and Effect Size |
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Term
| What can be done to Increase Power? (3) |
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Definition
1. Increase Sample Size
2. Increase the effect size
3. Set alpha at a more lenient level |
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Term
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Definition
Identify the target population of the study
Identify the eligible members of the target population
Decide whether probability or non-probability sampling is necessary
Choose a probability sample design (if necessary)
Choose a non-probability sample design (if necessary)
Calculate sample size requirements
Select the sample |
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