Data for Exercise 10.28 and 10.29

`Carbon`

A data frame/tibble with 24 observations on two variables

- CO
carbon monoxide measured (in parts per million)

- site
a factor with levels

`SiteA`

,`SiteB`

, and`SiteC`

Kitchens, L. J. (2003) *Basic Statistics and Data Analysis*.
Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning.

```
boxplot(CO ~ site, data = Carbon, col = "lightgreen")
kruskal.test(CO ~ site, data = Carbon)
#>
#> Kruskal-Wallis rank sum test
#>
#> data: CO by site
#> Kruskal-Wallis chi-squared = 4.9083, df = 2, p-value = 0.08594
#>
```