Data set: Weights
In the process of studying the effect of sleep on mammals, T. Allison and D. Cicchetti collected the brain weights (in grams) and body weights ( in kilograms) of 62 mammals.5 In the data set, you can see the measurements for these two variables for each of the 62 animals studied.
a. Create a scatterplot and regression line to predict BrainWt from BodyWt and appropriate residual plots. Even though the R2 value is reasonable, it is clear that there are extreme outliers on both the X and Y axes.
b. Create a scatterplot and regression line to predict log( BrainWt) from log( BodyWt). Create the appropriate residual plots and describe how the transformation impacted the validity of the linear regression model.
c. The African elephant weighs 6654 kg. Use both models created in Parts A and B to estimate the African elephant’s brain weight. Which model provides a more accurate estimate? Explain how this corresponds to the residual plots created in both questions.