Final answer:
The sum of squares between groups measures the variability of the sample treatment means around the overall mean, while the sum of squares within groups measures the variability within samples due to chance factors.
Step-by-step explanation:
The sum of squares between groups (SSbetween) measures the variability of the sample treatment means around the overall mean. It represents the variation among the different samples. On the other hand, the sum of squares within groups (SSwithin) measures the variability within samples that is due to chance or individual factors.
To calculate the sum of squares mean, you add together squared quantities, which may be weighted. The mean squares (MS) between groups and within groups are calculated by dividing each sum of squares by its respective degrees of freedom.