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There are two types of variables, numerical and categorical.
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Numerical variables can further be categorized as continuous or discrete.
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We will define observational studies and experiments and discuss correlation and causation.
Observational
Experiment
In an experiments on the other hand, researchers randomly assign subjects to treatments and can, therefore, establish causal connections between the explanatory and response variables.
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The title of the article says, breakfast cereal keeps girls slim, but there actually three possible explanations here.
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Such extraneous variables that affect both the explanatory and the response variable and that make it seem like there's a relationship between them are called confounding variables.
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