Interactive · from Volume 1
Pearson vs Spearman
Sixty patients, fatigue against six-minute walk distance. The relationship is strong but curved, so the two coefficients tell different stories. Pull the straighten slider and watch Pearson climb to meet Spearman, or move the points yourself.
Spearman is Pearson computed on ranks. Drag this all the way and both variables become their own ranks, at which point the two coefficients agree exactly. That is the whole difference between them, in one control.
Drag across the plot to select several
Drag one point to move it. Drag across empty space to lasso a group, then drag any of them to move the whole selection. Shift adds to a selection. Keyboard: tab to a point and use the arrow keys.
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