SME
Grade 11 Math · Algebra 2
Sampling methods and study design: surveys, experiments and observational studies
Compare surveys, observational studies and experiments, and see why only random assignment can show cause and effect.
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12 of the 48 people are picked at random and asked a question.
Their answers estimate the whole group’s.
Assumptions
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A sample is taken from the population; a random sample stands for it fairly.
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Only an experiment assigns treatments at random, so only it can show cause and effect.
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A control group, often given a placebo, is what the treatment is compared with.
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More problem types
Which sampling method?
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Survey, observational study or experiment?
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Name the bias
Use this for “A website asks readers to vote in a poll. What kind of bias is this?”