Chapter 3

3.1, 3.3, 3.4, 3.7, 3.9, 3.13

## Data for 3.9
credit <- read.table("https://raw.githubusercontent.com/alanagresti/categorical-data/refs/heads/master/Credit.dat", header = TRUE)

credit$any_card <- 1L*(credit$cards > 0)

Chapter 4

4.5, 4.9, 4.13