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Unformatted text preview: The University of Western Ontario Department of Statistical and Actuarial Sciences Statistical Sciences 3859A Assignment 3 Due Date: 11 November, 2009 1. Use R to analyze the data from the rolling bottle experiment (the data can be sourced in R from bottlerolling.R ): (a) Prepare scatterplots of distance versus rampheight and distance versus water . Describe the patterns you see. (b) Use the subset() command to remove the observations for which the water amount was 0 g. (c) Fit a multiple regression model relating distance to the other two variables. When fitting the model, consider the following questions: Would you recommend a square root transformation of the distance variable? Is an interaction term appropriate? Is it better to work with the square root of rampheight or with untransformed rampheight ? Using appropriate graphs, explain why you have made your choices. Write out the fitted model. (d) Construct a plot of the residuals versus the fitted values. Are there problems with your model? What remedy would you suggest? (e) Prepare a sequential analysis of variance table. Does it make a big difference which order the explanatory variables enter the model? Explain briefly....
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This note was uploaded on 11/25/2010 for the course AS 3859 taught by Professor Braun during the Fall '10 term at UWO.
- Fall '10