Illustrates test of equality of medians with the Kruskal Wallis test

Data for Exercise 10.52

Median

Format

A data frame/tibble with 45 observations on two variables

sample

a vector with values Sample1, Sample 2, and Sample 3

value

a numeric vector

References

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

Examples

boxplot(value ~ sample, data = Median, col = rainbow(3))

anova(lm(value ~ sample, data = Median))
#> Analysis of Variance Table
#> 
#> Response: value
#>           Df  Sum Sq Mean Sq F value  Pr(>F)  
#> sample     2  309.38 154.689  2.5634 0.08905 .
#> Residuals 42 2534.53  60.346                  
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
kruskal.test(value ~ factor(sample), data = Median)
#> 
#> 	Kruskal-Wallis rank sum test
#> 
#> data:  value by factor(sample)
#> Kruskal-Wallis chi-squared = 5.1308, df = 2, p-value = 0.07689
#>