The "Sum of Squares" is a statistical concept used to measure the variability or dispersion of a set of data points. It is calculated by taking the difference between each data point and the mean, squaring those differences, and then summing them up. This helps in understanding how spread out the data is around the average value. In the context of statistics, the Sum of Squares is often used in various analyses, such as ANOVA (Analysis of Variance) and regression analysis. It provides insight into the overall variability in the data, which can be crucial for making informed decisions based on statistical findings.