Sxx Variance !!hot!! -

Sxx=∑xi2−(∑xi)2ncap S sub x x end-sub equals sum of x sub i squared minus the fraction with numerator open paren sum of x sub i close paren squared and denominator n end-fraction

helps partition how much of that variation is explained by the independent variable 5. Visualizing Variation The following graph illustrates how individual data points relate to their mean Sxxcap S sub x x end-sub sxx variance

This cognitive blind spot is why SXX variance is so often ignored. We prefer the Standard Deviation because it gives us a number in the same units as the data (dollars, days, degrees). SXX gives us "squared dollars" or "squared days"—units that make no intuitive sense to a human reader. Sxx=∑xi2−(∑xi)2ncap S sub x x end-sub equals sum