Data for Exercise 7.58
Speed
A data frame/tibble with 15 observations on four variables
reading comprehension score before taking a speed-reading course
reading comprehension score after taking a speed-reading course
after - before (comprehension reading scores)
signed ranked differences
Kitchens, L. J. (2003) Basic Statistics and Data Analysis. Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning.
t.test(Speed$differ, alternative = "greater")
#>
#> One Sample t-test
#>
#> data: Speed$differ
#> t = 0.99038, df = 14, p-value = 0.1694
#> alternative hypothesis: true mean is greater than 0
#> 95 percent confidence interval:
#> -2.490967 Inf
#> sample estimates:
#> mean of x
#> 3.2
#>
t.test(Speed$signranks, alternative = "greater")
#>
#> One Sample t-test
#>
#> data: Speed$signranks
#> t = 2.7691, df = 14, p-value = 0.007534
#> alternative hypothesis: true mean is greater than 0
#> 95 percent confidence interval:
#> 1.965284 Inf
#> sample estimates:
#> mean of x
#> 5.4
#>
wilcox.test(Pair(Speed$after, Speed$before) ~ 1, data = Speed, alternative = "greater")
#> Warning: cannot compute exact p-value with ties
#>
#> Wilcoxon signed rank test with continuity correction
#>
#> data: Pair(Speed$after, Speed$before)
#> V = 100.5, p-value = 0.01144
#> alternative hypothesis: true location shift is greater than 0
#>