```
# This dataset was created as follows
# \donttest{
n <- 250
set.seed(0)
cross <- rbind(matrix(rnorm(n*2), n, 2) %*% diag(c(1,9)),
matrix(rnorm(n*2), n, 2) %*% diag(c(1,9))[,2:1])
cross <- cbind(c(rep(1,n),rep(2,n)), cross)
# }
```

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