We will now examine the Carseats
data, which is part of the ISLR2
library.
(Don’t forget to load and if necessary install the package first in RStudio.)
We will attempt to predict Sales
(child car seat sales) in 400 locations based on a number of predictors.
> head(Carseats)
> names(Carseats)
[1] "Sales" "CompPrice" "Income" "Advertising" "Population"
[6] "Price" "ShelveLoc" "Age" "Education" "Urban"
[11] "US"
The Carseats
data includes qualitative predictors such as ShelveLoc
, an indicator of the quality of
the shelving location—that is, the space within
a store in which the car seat is displayed—at each location.
The predictor ShelveLoc
takes on three possible values, Bad, Medium, and Good.
Given a qualitative variable such as ShelveLoc
, R generates dummy variables
automatically.
Try to use the levels()
function to check the three possible values of ShelveLoc
yourself:
Assume that:
ISLR2
library has been loadedCarseats
dataset has been loaded and attached