Illustrates inferences based on pooled t-test versus Wilcoxon rank sum test

Data for Exercise 7.40

Backtoback

Format

A data frame/tibble with 24 observations on two variables

score

a numeric vector

group

a numeric vector

References

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

Examples

wilcox.test(score ~ group, data = Backtoback)
#> Warning: cannot compute exact p-value with ties
#> 
#> 	Wilcoxon rank sum test with continuity correction
#> 
#> data:  score by group
#> W = 70, p-value = 0.931
#> alternative hypothesis: true location shift is not equal to 0
#> 
t.test(score ~ group, data = Backtoback)
#> 
#> 	Welch Two Sample t-test
#> 
#> data:  score by group
#> t = -0.063039, df = 21.914, p-value = 0.9503
#> alternative hypothesis: true difference in means between group 1 and group 2 is not equal to 0
#> 95 percent confidence interval:
#>  -19.77837  18.61170
#> sample estimates:
#> mean in group 1 mean in group 2 
#>        193.6667        194.2500 
#>