The type of data collected and how the associated sampling takes place depend on the statistical question asked.
There are a number of aspects of data collection that need to be considered when carrying out a statistical investigation.
- Choose the questions (e.g. "Do you like …?", "How tall is …?") that will determine the type of data collected (e.g. categorical, numerical).
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Choose a sample size that will allow confidence in the conclusion.
Use repeated sampling to demonstrate how much variation occurs in samples of different sizes.
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Avoid bias in data collection.
Explore sources of bias in various contexts where data are collected.
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Understand the importance of random selection.
Explore various methods of random sampling.
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Know the relationship between samples and populations.
Learn to define populations and samples in various statistical contexts.