Least squares — minimising SSR
OLS picks the line that minimises the sum of squared residuals, SSR = Σ(yᵢ − ŷᵢ)². Residuals are the vertical gaps from each point to the line. Drag your blue line and try to beat the gold OLS line on SSR.
SSR — your line vs OLS26 vs 26
OLS line ŷ = 2.1 + 1.55xSSR (OLS, min) 26R² (OLS) 93%
Your intercept b₀2.1
Your slope b₁1.55
Your line sits exactly on the OLS line, so the two SSRs are equal at the minimum 26. Nudge a slider and the loss can only go up.