Reaction effects of 4 drugs on 25 subjects with a nervous disorder

Data for Example 10.3

Nervous

Format

A data frame/tibble with 25 observations on two variables

react

a numeric vector representing reaction time

drug

a numeric vector indicating each of the 4 drugs

References

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

Examples

boxplot(react ~ drug, data = Nervous, col = rainbow(4))

model <- aov(react ~ factor(drug), data = Nervous)
summary(model)
#>              Df Sum Sq Mean Sq F value  Pr(>F)    
#> factor(drug)  3  43.02  14.340   8.179 0.00085 ***
#> Residuals    21  36.82   1.753                    
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
TukeyHSD(model)
#>   Tukey multiple comparisons of means
#>     95% family-wise confidence level
#> 
#> Fit: aov(formula = react ~ factor(drug), data = Nervous)
#> 
#> $`factor(drug)`
#>           diff        lwr        upr     p adj
#> 2-1  0.3142857 -1.8467970  2.4753684 0.9768997
#> 3-1  2.4571429  0.2960602  4.6182256 0.0221431
#> 4-1 -1.0666667 -3.3015276  1.1681943 0.5547136
#> 3-2  2.1428571  0.1700676  4.1156467 0.0301086
#> 4-2 -1.3809524 -3.4342969  0.6723921 0.2686560
#> 4-3 -3.5238095 -5.5771540 -1.4704650 0.0005391
#> 
plot(TukeyHSD(model), las = 1)