Data for Exercise 10.44
TreatmentsFormat
A data frame/tibble with 24 observations on two variables
- score
score from an experiment
- group
factor with levels 1, 2, and 3
References
Kitchens, L. J. (2003) Basic Statistics and Data Analysis. Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning.
Examples
boxplot(score ~ group, data = Treatments, col = "violet")
summary(aov(score ~ group, data = Treatments))
#> Df Sum Sq Mean Sq F value Pr(>F)
#> group 2 262.7 131.37 4.05 0.0325 *
#> Residuals 21 681.2 32.44
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
summary(lm(score ~ group, data = Treatments))
#>
#> Call:
#> lm(formula = score ~ group, data = Treatments)
#>
#> Residuals:
#> Min 1Q Median 3Q Max
#> -11.125 -2.469 -0.250 3.875 9.875
#>
#> Coefficients:
#> Estimate Std. Error t value Pr(>|t|)
#> (Intercept) 32.125 2.014 15.953 3.26e-13 ***
#> group2 8.000 2.848 2.809 0.0105 *
#> group3 5.125 2.848 1.800 0.0863 .
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#>
#> Residual standard error: 5.696 on 21 degrees of freedom
#> Multiple R-squared: 0.2783, Adjusted R-squared: 0.2096
#> F-statistic: 4.05 on 2 and 21 DF, p-value: 0.03255
#>
anova(lm(score ~ group, data = Treatments))
#> Analysis of Variance Table
#>
#> Response: score
#> Df Sum Sq Mean Sq F value Pr(>F)
#> group 2 262.75 131.38 4.0497 0.03255 *
#> Residuals 21 681.25 32.44
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1