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From Algorithms to Z-Scores - matloff - University of California, Davis

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CONTENTS xv<br />

17.2.3 Logistic Regression: a Common Parametric Model for the Regression Function<br />

in Classification Problems . . . . . . . . . . . . . . . . . . . . . . . . . . 336<br />

17.2.3.1 The Logistic Model: Motivations . . . . . . . . . . . . . . . . . . . . 337<br />

17.2.4 Esimation and Inference for Logit Coefficients . . . . . . . . . . . . . . . . . . 339<br />

17.2.5 Example: Forest Cover Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 339<br />

17.2.6 What If Y Doesn’t Have a Marginal Distribution? . . . . . . . . . . . . . . . 340<br />

17.3 Nonparametric Estimation <strong>of</strong> Regression and Classification Functions . . . . . . . . . 341<br />

17.3.1 Methods Based on Estimating mY ;X(t) . . . . . . . . . . . . . . . . . . . . . 341<br />

17.3.1.1 Nearest-Neighbor Methods . . . . . . . . . . . . . . . . . . . . . . . 342<br />

17.3.1.2 Kernel-Based Methods . . . . . . . . . . . . . . . . . . . . . . . . . 344<br />

17.3.1.3 The Naive Bayes Method . . . . . . . . . . . . . . . . . . . . . . . . 345<br />

17.3.2 Methods Based on Estimating Classification Boundaries . . . . . . . . . . . . 346<br />

17.3.2.1 Support Vec<strong>to</strong>r Machines (SVMs) . . . . . . . . . . . . . . . . . . . 346<br />

17.3.2.2 CART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347<br />

17.3.3 Comparison <strong>of</strong> Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349<br />

17.4 Symmetric Relations Among Several Variables . . . . . . . . . . . . . . . . . . . . . 350<br />

17.4.1 Principal Components Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 351<br />

17.4.2 How <strong>to</strong> Calculate Them . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351<br />

17.4.3 Example: Forest Cover Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 353<br />

17.4.4 Log-Linear Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353<br />

17.4.4.1 The Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354<br />

17.4.4.2 The Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354<br />

17.4.4.3 The Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355<br />

17.4.4.4 Parameter Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . 356<br />

17.4.4.5 The Goal: Parsimony Again . . . . . . . . . . . . . . . . . . . . . . 357<br />

17.5 Simpson’s (Non-)Paradox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357

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