Statistical Sciences 2244A/B Chapter Notes - Chapter 3, 23: Dependent And Independent Variables, Scatter Plot, Standard Deviation
15 Jan 2017
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Response (dependent) variable: measures the outcome of the study. Explanatory (independent) variable: may explain/influence the response variable. Goal of study is to show that the explanatory variable is actually responsible for change in the response variable. Graph to display relationship between 2 quantitative variables. Increase in one variable is linked with increase in the other variable. Increase in one variable is linked with decrease in the other variable. Points lay close to a straight line. +/- correlation tells you about +/- association. The closer r is to |1|, the more linear the relationship is. Cannot describe curved relationships r calculated from averaged data is stronger than raw individual data. Averaged data has less individual-to-individual variation r is not a full summary of 2-variable data (no outliers/clusters) Outliers r is not resistant, sensitive to outliers. Use a different symbol/colour to specific a categorial variable. Lets us see the effects of a 3rd variable on x and y.
