Final answer:
The 'error' degrees of freedom in ANOVA come from the residual variability or unexplained variation within each group.
Step-by-step explanation:
The 'error' degrees of freedom in ANOVA come from the residual variability, which represents the unexplained variation or chance variation within each group.
In ANOVA, the variability in the data can be decomposed into three components: the between-group variability, the within-group variability, and the total variability. The 'error' degrees of freedom specifically pertain to the within-group variability, as it compares the values of each group to its own group mean.
The ANOVA test uses the ratio of the between-group mean square (MSbetween) to the within-group mean square (MSwithin) to calculate the F statistic and determine if there is a significant difference between the group means. The 'error' degrees of freedom are associated with the denominator degrees of freedom in this F ratio.