Draw a scatterplot of Weight versus Age, and comment on the applicability of the usual assumptions of the linear regression model. Also draw a scatterplot of SD versus Age, and summarize the...

Draw a scatterplot of Weight versus Age, and comment on the applicability of the usual assumptions of the linear regression model. Also draw a scatterplot of SD versus Age, and summarize the information in this plot.

To fit a simple linear regression model with Weight as the response, wls should be used with variance function Var (Weight|Age) = nσ₂
/SD₂. Sample sizes are large enough to assume the SD are population values. Fit the wls model.