NUMB3RS: Season 3 - "Hardball"

Least Squares Regression & MLB Statistical Anomalies

Difficulty: StatisticsTI Activity PDF
Step 1 of 6

Bivariate Data and Informal Fits

When analyzing baseball statistics, fans and managers notice that power hitters who hit many home runs (xx) also tend to strike out (yy) with higher frequency. To model this positive correlation, we look for a linear relationship:

y=mx+by = mx + b

Before calculators automate this, mathematicians used a trial-and-error approach to manually place a line through a scatter plot so that it passes through the 'middle' of the data.

MLB Regression Simulator

Explore Sum of Squared Residuals (SSR) dynamically.

60901201501801020304050Home Runs (x)Strikeouts (y)Player A Home Runs: 12 Strikeouts: 80Player B Home Runs: 22 Strikeouts: 96Player C Home Runs: 32 Strikeouts: 124Player D Home Runs: 42 Strikeouts: 138Player E Home Runs: 48 Strikeouts: 156
Interactive Formula

y = 2.00x + 55.00

Sum of Squared Residuals (SSR)

61.00

Slope (m): 2.00Range: 1.0 - 3.5
Y-Intercept (b): 55.00Range: 30 - 80

Geometric Breakdown Table

PlayerHR (x)Actual SO (y)Predicted (ŷ)Residual (e)e² (Area of Square)
Player A128079.00+1.001.00
Player B229699.00-3.009.00
Player C32124119.00+5.0025.00
Player D42138139.00-1.001.00
Player E48156151.00+5.0025.00
Sum of Squared Residuals (SSR)61.00