Data for Exercise 8.21

`Snore`

A data frame/tibble with 2,484 observations on two variables

- snore
factor with levels

`nonsnorer`

,`ocassional snorer`

,`nearly every night`

, and`snores every night`

- heartdisease
factor indicating whether the indiviudal has heart disease (

`no`

or`yes`

)

Norton, P. and Dunn, E. (1985), Snoring as a Risk Factor for Disease,
*British Medical Journal, 291*,
630-632.

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

```
T1 <- xtabs(~ heartdisease + snore, data = Snore)
T1
#> snore
#> heartdisease nonsnorer occassional snorer nearly every night snores every night
#> yes 24 35 21 30
#> no 1355 603 192 224
chisq.test(T1)
#>
#> Pearson's Chi-squared test
#>
#> data: T1
#> X-squared = 72.782, df = 3, p-value = 1.082e-15
#>
rm(T1)
```