Analysis of Variance

Example usage


anova(ToothGrowth, dep='len', factors=c('dose', 'supp'))

#  ───────────────────────────────────────────────────────────────────────
#                 Sum of Squares    df    Mean Square    F        p
#  ───────────────────────────────────────────────────────────────────────
#    dose                   2426     2         1213.2    92.00    < .001
#    supp                    205     1          205.4    15.57    < .001
#    dose:supp               108     2           54.2     4.11     0.022
#    Residuals               712    54           13.2
#  ───────────────────────────────────────────────────────────────────────


data — the data as a data frame

dep — a string naming the dependent variable from data, variable must be numeric

factors — a vector of strings naming the fixed factors from data

modelTerms — a list of character vectors describing the terms to go into the model

ss'1', '2' or '3' (default), the sum of squares to use

effectSize — one or more of 'eta', 'partEta', or 'omega'; use η², partial η², and ω² effect sizes, respectively

contrasts — a list of lists specifying the factor and type of contrast to use, one of 'deviation', 'simple', 'difference', 'helmert', 'repeated' or 'polynomial'

plotHAxis — a string naming the variable placed on the horizontal axis of the plot

plotSepLines — a string naming the variable represented as separate lines on the plot

plotSepPlots — a string naming the variable to separate over to form multiple plots

postHoc — a list of terms to perform post-hoc tests on

postHocCorr — one or more of 'none', 'tukey', 'scheffe', 'bonf', or 'holm'; provide no, Tukey, Scheffe, Bonferroni, and Holm Post Hoc corrections respectively

descStatsTRUE or FALSE (default), provide descriptive statistics

homoTRUE or FALSE (default), perform homogeneity tests

qqTRUE or FALSE (default), provide a Q-Q plot of residuals

plotError'none', 'ci' (default), or 'se'. Use no error bars, use confidence intervals, or use standard errors on the plots, respectively

ciWidth — a number between 50 and 99.9 (default: 95) specifying the confidence interval width