Book Image

Hands-On Ensemble Learning with R

By : Prabhanjan Narayanachar Tattar
Book Image

Hands-On Ensemble Learning with R

By: Prabhanjan Narayanachar Tattar

Overview of this book

Ensemble techniques are used for combining two or more similar or dissimilar machine learning algorithms to create a stronger model. Such a model delivers superior prediction power and can give your datasets a boost in accuracy. Hands-On Ensemble Learning with R begins with the important statistical resampling methods. You will then walk through the central trilogy of ensemble techniques – bagging, random forest, and boosting – then you'll learn how they can be used to provide greater accuracy on large datasets using popular R packages. You will learn how to combine model predictions using different machine learning algorithms to build ensemble models. In addition to this, you will explore how to improve the performance of your ensemble models. By the end of this book, you will have learned how machine learning algorithms can be combined to reduce common problems and build simple efficient ensemble models with the help of real-world examples.
Table of Contents (17 chapters)
Hands-On Ensemble Learning with R
Contributors
Preface
12
What's Next?
Index

Bootstrapping regression models


The US Crime dataset introduced in Chapter 1, Introduction to Ensemble Techniques, is an example of why the linear regression model might be a good fit. In this example, we are interested in understanding the crime rate (R) as a function of thirteen related variables such as average age, the southern state indicator, and so on. Mathematically, the linear regression model is as follows:

Here, are the p-covariates, is the intercept term, are the regression coefficients, and is the error term assumed to follow a normal distribution . The covariates can be written in a vector form and the ith observation can be summarized as , where . The n observations , are assumed to be stochastically independent. The linear regression model has been detailed in many classical regression books; see Draper and Smith (1999), for instance. A recent book that details the implementation of the linear regression model in R is Ciaburro (2018). As the reader might have guessed,...