raleighnet.org

Why do we divide the total of the squared deviations by n-1, rather than n? Recall that the sum of the deviations is known to be zero, so given the first n-1 deviations, we can always calculate the remaining deviation. This means only n-1 of the deviations can vary freely — the last value is constrained by the values of the preceding deviations. This figure, n-1, is known as the degrees of freedom and is a value that will become more important in the chapters that follows.

I’ve read that paragraph 10 times. I think I finally understand what it’s saying, but I don’t think it really answers the question it begins by asking. I need more math training…..I need A LOT MORE math training.