SOURCEBOOK

R | Data Analysis

One Way ANOVA

Prior to the steps below, enter the data as appropriate for the analyses (described elsewhere). As always, the following commands should be typed directly in the R console window.

Obtaining Descriptive Statistics

Get the grand mean for the variable and the mean and standard deviation for the dependent variable for each of the levels.

mean(Outcome)
tapply(Outcome, Factor, function(x) c(length(x), mean(x), sd(x)))

Obtaining Inferential Statistics

Get the analysis of variance source table with test of statistical significance.

Results <- aov(Outcome~Factor)
summary(Results)