Curious Pivot Points of Least-Squares Regression
It has been shown that for a given set of points in a plane, the least-squares regression line pivots about a fixed point when any single point in the set is repeated. We consider what happens when more than one point is repeated. Geometrically, we describe the regions where pivot points may lie under all possible combinations of repetitions. The underlying framework of this pivoting is explored, yielding new open-ended questions.
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