Data for Example 7.18

`Lowabil`

A data frame/tibble with 12 observations on three variables

- pair
a numeric indicator of pair

- experiment
score of the child with the experimental method

- control
score of the child with the standard method

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

```
diff = Lowabil$experiment - Lowabil$control
qqnorm(diff)
qqline(diff)
shapiro.test(diff)
#>
#> Shapiro-Wilk normality test
#>
#> data: diff
#> W = 0.95014, p-value = 0.6391
#>
t.test(Lowabil$experiment, Lowabil$control, paired = TRUE)
#>
#> Paired t-test
#>
#> data: Lowabil$experiment and Lowabil$control
#> t = 3.6035, df = 11, p-value = 0.004144
#> alternative hypothesis: true difference in means is not equal to 0
#> 95 percent confidence interval:
#> 1.427113 5.906220
#> sample estimates:
#> mean of the differences
#> 3.666667
#>
# OR
t.test(diff)
#>
#> One Sample t-test
#>
#> data: diff
#> t = 3.6035, df = 11, p-value = 0.004144
#> alternative hypothesis: true mean is not equal to 0
#> 95 percent confidence interval:
#> 1.427113 5.906220
#> sample estimates:
#> mean of x
#> 3.666667
#>
rm(diff)
```