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

Introduction


In the last two chapters (on regression and classification), we focused on understanding and implementing the various machine learning algorithms in the supervised learning category on a given dataset pertaining to a problem.

In this chapter, we will focus more on effectively using the features of the dataset to build the best performing model. Often in many datasets, the feature space is quite large (with many features). The model performance takes a hit as the patterns are hard to find and often much noise is present in the data. Feature selections are specific methods that are used to identify the importance of each feature and assign a score to each. We can then select the top 10 or 15 features (or even more) based on the score for building our model.

Another possibility is to create new variables using a linear combination of all the input variables. This helps in keeping the representation of all variables and reducing the dimensionality of feature space. However, such a...