39 lines
2.1 KiB
Markdown
39 lines
2.1 KiB
Markdown
(Ch 19, stat 1040)
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| Term | Definition |
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| ---- | ---- |
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| Qualitative | A descriptive value (red, blue, high, low) |
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| Quantitative | A numerical value (7, 8, 9) |
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| Population | The entire set of existing units that investigators wish to study |
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| Sample | A portion or subset of the population |
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| Parameter | A number that describes a characteristic of a *population* (*10%* of US senators voted for something) |
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| Statistic | A number that describes a *sample* characteristic (*71%* of Americans feel that ...) |
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> A global consumer survey reported that 6% of US taxpayers used or owned cryptocurrency in 2020. The US government is interested in knowing if this percentage has increased. The University of Chicago surveys 1,004 taxpayers and finds that 13% have used or owned crypto in the past year (2021)
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In the above example:
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- The *population* was *US taxpayers*
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- The *parameter* was *6%*
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- The *sample* was *1004 taxpayers*
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- The *statistic* was *13%*
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An ideal sample will represent the whole population.
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## Sampling
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| Sample Type | Description |
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| ---- | ---- |
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| Simple random | Advantages:<br>- Procedure is impartial<br>- Law of Averages<br>Disadvantages<br>- Not always possible<br>- Can be very expensive |
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| Quota Sampling | Attempts to get certain proportions based on key characteristics. Quota sampling doesn't guarantee that the selection is an accurate representation. |
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| Cluster Sampling | Divide population into subgroups, randomly select a subgroup, and sample all of the subjects in that group |
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| Convenience | Sampling done near to the researcher because it's easier. |
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## Simple Random Samples
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## Bias
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| Bias Type | Description |
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| ---- | ---- |
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| Selection | When the procedure that selects the sample is biased |
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| Non-Response | Those that don't respond to a survey may have different characteristics than those that do respond |
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| Response | When the question is worded in a leading way to elicit a certain response. |
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| Volunteer response | Self selecting, individuals volunteer to answer |
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| Measurement | Interviewing method influences the response, uses loaded words or ambiguities. |
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(Ch 20, stat 1040)
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