Researchers observed the following data on 20 individuals with high blood pressure:

Our goal is to build a model for blood pressure as a function of (some subset) of the other variables. In this case all of our variables are quantitative, so we can get a quick look at their relationships using the a pairs plot.

BP <- read.csv("")

# Better than the standard pairs plot is the generalized pairs plot. 

Hint: use cor to calculate the correlation coefficient matrix.

A First Model

Weight seems to be highly correlated with BP, so as a first step, we should understand how well a simple linear model for blood pressure as a function of weight works. Keep in mind that it accords with our intuition that there would be a strong link between a person’s weight and their blood pressure.

xyplot(BP ~ Weight, data=BP, pch=19, alpha=0.5, cex=1.5, type=c("p", "r"))