Data for Exercise 7.56

Spelling

Format

A data frame/tibble with nine observations on three variables

before

spelling score before a 2-week course of instruction

after

spelling score after a 2-week course of instruction

differ

after - before (spelling score)

References

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

Examples


qqnorm(Spelling$differ)
qqline(Spelling$differ)

shapiro.test(Spelling$differ)
#> 
#> 	Shapiro-Wilk normality test
#> 
#> data:  Spelling$differ
#> W = 0.9642, p-value = 0.8411
#> 
t.test(Spelling$before, Spelling$after, paired = TRUE)
#> 
#> 	Paired t-test
#> 
#> data:  Spelling$before and Spelling$after
#> t = -2.286, df = 8, p-value = 0.05159
#> alternative hypothesis: true difference in means is not equal to 0
#> 95 percent confidence interval:
#>  -6.02624912  0.02624912
#> sample estimates:
#> mean of the differences 
#>                      -3 
#> 
t.test(Spelling$differ)
#> 
#> 	One Sample t-test
#> 
#> data:  Spelling$differ
#> t = 2.286, df = 8, p-value = 0.05159
#> alternative hypothesis: true mean is not equal to 0
#> 95 percent confidence interval:
#>  -0.02624912  6.02624912
#> sample estimates:
#> mean of x 
#>         3 
#>