Fit a multiple linear regression y = b₀ + b₁x₁ + b₂x₂ for two predictors using normal equations.
Multiple linear regression fits a plane y = b₀ + b₁x₁ + b₂x₂ to data with two predictors. Coefficients are found by solving the normal equations (XᵀX)b = Xᵀy.
y = b₀ + b₁x₁ + b₂x₂, solved via (XᵀX)b = Xᵀy
This calculator uses a closed-form 3×3 normal equation solver for clarity and speed. For more predictors, matrix libraries or iterative methods are needed.
A negative bᵢ means that when xᵢ increases by 1 (holding the other predictor constant), y decreases by |bᵢ|.