Book Image

Applied Supervised Learning with R

By : Karthik Ramasubramanian, Jojo Moolayil
Book Image

Applied Supervised Learning with R

By: Karthik Ramasubramanian, Jojo Moolayil

Overview of this book

R provides excellent visualization features that are essential for exploring data before using it in automated learning. Applied Supervised Learning with R helps you cover the complete process of employing R to develop applications using supervised machine learning algorithms for your business needs. The book starts by helping you develop your analytical thinking to create a problem statement using business inputs and domain research. You will then learn different evaluation metrics that compare various algorithms, and later progress to using these metrics to select the best algorithm for your problem. After finalizing the algorithm you want to use, you will study the hyperparameter optimization technique to fine-tune your set of optimal parameters. The book demonstrates how you can add different regularization terms to avoid overfitting your model. By the end of this book, you will have gained the advanced skills you need for modeling a supervised machine learning algorithm that precisely fulfills your business needs.
Table of Contents (12 chapters)
Applied Supervised Learning with R
Preface

Residual versus Fitted Plot


This type of plot is between the fitted values and the residual (difference between actual and fitted values) from the lm() method. If the predictor and target variables have a non-linear relationship, the plot will help us identify.

In the following figure, the top plot shows the point scattered all around and the linear relationship between the predictor and target variable is clearly captured. In the bottom plot, the unexplained non-linear relationship is left out in the residuals, and hence the curve. The bottom plot clearly shows it is not the right fit for a linear regression model, a violation of the linear relationship between the predictor and target variable:

Figure 4.4: [Top] Residual versus fitted plot of the linear function. [Bottom] Residual versus fitted plot of the quadratic function