STA220H1 Chapter Notes - Chapter 2: Categorical Variable, The Who
10 Dec 2013
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STA220H1 Full Course Notes
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The five w"s: who, what, when, where, and (if possible) why and how. We must know at least the who, what and why to be able to say anything useful based on the data. A variable gives information about each of the cases. The why helps us decided which way to treat the variables. We treat variables in two different ways, as categorical or quantitative: Categorical (qualitative) variables identify a category for each case. Quantitative variables record measurements or amounts of something; they must have units. Sometimes we treat a variable as categorical or quantitative depending on how we want to learn from it. Data: systematically recorded information, whether numbers or labels, together with its context. Context: ideally tells who was measured, what was measured, how the data was collected, where the data was collected, and when and why the study was performed. Each row represents a case and each column represents a variable.
