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Practical 1 - plots


When we're asked to analyse data in paragraph 2, the method suggest than we plot boxplots and scatter plots of response vs. each covariate

But basically box plots and scatterplots are the same when plotting response versus weight or horsepower as every car's got a different value for these variables. On the contrary, if we want to analyse response vs type of transmission, box plots are usefull.

Do we have to choose between scatter and box plots ? Do we need to tell the relevance of each variables or only the ones that we think they're relevant ?


Posted by Pierre Morel on Tuesday 12 November 2013 at 17:29
Boxplots and scatter plots are not the same thing. Boxplots concern each of the variables marginally while scatter plots contrast two variables (see e.g. http://en.wikipedia.org/wiki/Boxplot and http://en.wikipedia.org/wiki/Scatter_plot). What we would like to see in Section II is boxplots for 100/CityMPG, Weight and Horsepower/Weight as well as scatter plots for 100/CityMPG vs. Weight and 100/CityMPG vs. Horsepower/Weight. So 5 plots in total (with explanations and interpretation!). There's no need to provide plots for the variables that are not used in the model.
Posted by Mikael Kuusela on Tuesday 12 November 2013 at 20:18
Ok, thank you for the answer.
Posted by Pierre Morel on Sunday 17 November 2013 at 16:26