Simple Linear Regression • Simple linear regression model: • Yi= • Distribution of errors for i=1, 2, …, n
Simple Linear Regression • In practice, do not know the values of the ’s nor 2 • Use data to estimate model parameters giving estimated regression equation • Want to get the “line of best fit”…what does this mean?
Apartment Example
Least Squares • Estimation via least squares: Q= • Know how to derive • For simple linear regression and multiple linear regression • Related simplified models are fair game
Properties • Know properties of estimators and also residuals • Example: sum of residuals is • Show estimates of regression parameters are unbiased • How do you use the estimated regression line (function)?
Maximum likelihood • Know how to derive MLE for regression parameters and variance
Inference • Interested in making inference about regression parameters are the function • Example: • Inference about i: • Prediction intervals: • Confidence intervals:
Inference • Interested in making inference about regression parameters are the function • Example: • Inference about i: • Simultaneous Inference:
Residual Diagnostics • Motivation • Plots • Remedial Measures…when to transform X or Y
Diagnostics • Could also do a Lack of Fit Test
Multiple regression • Derivations, inference • R 2 and adjusted R 2 • Extra sums of squares: • Multi-collinearity • Model Building: • Criteria and all sub-sets • Automatic methods
Final Steps • Model Validation: • Partial Regression Plots: