ISLR An Introduction to Statistical Learning, Gareth James, Daniela Witten, Trevor Hastie and Robert Tibshirani,

3 Linear Regression 59

3.1 Simple Linear Regression . . . . . . . . . . . . . . . . . . . 61

3.1.1 Estimating the Coefficients . . . . . . . . . . . . . . 61

3.1.2 Assessing the Accuracy of the Coefficient Estimates . . . . . . . . . . . . . . . . . . . . . . . . 63

3.1.3 Assessing the Accuracy of the Model . . . . . . . . . 68

3.2 Multiple Linear Regression . . . . . . . . . . . . . . . . . . 71

3.2.1 Estimating the Regression Coefficients . . . . . . . . 72

3.2.2 Some Important Questions . . . . . . . . . . . . . . 75

3.3 Other Considerations in the Regression Model . . . . . . . . 82

3.3.1 Qualitative Predictors . . . . . . . . . . . . . . . . . 82

3.3.2 Extensions of the Linear Model . . . . . . . . . . . . 86

3.3.3 Potential Problems . . . . . . . . . . . . . . . . . . . 92

3.4 The Marketing Plan . . . . . . . . . . . . . . . . . . . . . . 102

3.5 Comparison of Linear Regression with K-Nearest Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104