Graphical display of data and models

A 2-dimensional scatterplot shows the relationship between two numerical variables, Y and X. This can be extended to situations with a response, Y, and two explanatory variables, X and Z with a 3-dimensional scatterplot.

A simple linear model can be represented by a line on a 2-dimensional scatterplot and we will show that a multiple regression model can also be displayed on a 3-dimensional scatterplot.

Unfortunately regression models with three or more explanatory variables cannot be displayed graphically, but the main concepts in multiple regression can be illustrated for models for a response Y and two explanatory variables, X and Z.

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