Book Image

Practical Machine Learning with R

By : Brindha Priyadarshini Jeyaraman, Ludvig Renbo Olsen, Monicah Wambugu
Book Image

Practical Machine Learning with R

By: Brindha Priyadarshini Jeyaraman, Ludvig Renbo Olsen, Monicah Wambugu

Overview of this book

With huge amounts of data being generated every moment, businesses need applications that apply complex mathematical calculations to data repeatedly and at speed. With machine learning techniques and R, you can easily develop these kinds of applications in an efficient way. Practical Machine Learning with R begins by helping you grasp the basics of machine learning methods, while also highlighting how and why they work. You will understand how to get these algorithms to work in practice, rather than focusing on mathematical derivations. As you progress from one chapter to another, you will gain hands-on experience of building a machine learning solution in R. Next, using R packages such as rpart, random forest, and multiple imputation by chained equations (MICE), you will learn to implement algorithms including neural net classifier, decision trees, and linear and non-linear regression. As you progress through the book, you’ll delve into various machine learning techniques for both supervised and unsupervised learning approaches. In addition to this, you’ll gain insights into partitioning the datasets and mechanisms to evaluate the results from each model and be able to compare them. By the end of this book, you will have gained expertise in solving your business problems, starting by forming a good problem statement, selecting the most appropriate model to solve your problem, and then ensuring that you do not overtrain it.
Table of Contents (8 chapters)

Feature Selection

There are two types of feature selection techniques: forward selection and backward selection.

  • Forward Selection: This is an approach that can be used for a labeled dataset. Basically, we start with one feature and build the model. We add more features in an incremental fashion and make a note of the accuracy as we go. We then select the combination of features that gave the highest level of accuracy while training the model. One con of this technique is that for a dataset with a large set of features, this is an extremely time-consuming process. Also, if an already-added feature is causing degradation of the performance of the model, we will not know it.
  • Backward Selection: In this approach, we will need a labeled dataset. All the features will be used to build the model. We will iteratively remove features to observe the performance of the model. We can then select the best combination (the combination that produced the highest performance). The con of this approach...