Sums of Squares is an important concept in Variation, playing a major role in ANOVA and Regression. 4 Keys to Understanding and plenty of graphics help to give the viewer an good conceptual understanding.
For the latest status of available and planned videos, visit the Videos page of this website.
Andrew A. (Andy) Jawlik is the author of the book, Statistics from A to Z -- Confusing Concepts Clarified, published by Wiley.