Book Image

Data Cleaning and Exploration with Machine Learning

By : Michael Walker
Book Image

Data Cleaning and Exploration with Machine Learning

By: Michael Walker

Overview of this book

Many individuals who know how to run machine learning algorithms do not have a good sense of the statistical assumptions they make and how to match the properties of the data to the algorithm for the best results. As you start with this book, models are carefully chosen to help you grasp the underlying data, including in-feature importance and correlation, and the distribution of features and targets. The first two parts of the book introduce you to techniques for preparing data for ML algorithms, without being bashful about using some ML techniques for data cleaning, including anomaly detection and feature selection. The book then helps you apply that knowledge to a wide variety of ML tasks. You’ll gain an understanding of popular supervised and unsupervised algorithms, how to prepare data for them, and how to evaluate them. Next, you’ll build models and understand the relationships in your data, as well as perform cleaning and exploration tasks with that data. You’ll make quick progress in studying the distribution of variables, identifying anomalies, and examining bivariate relationships, as you focus more on the accuracy of predictions in this book. By the end of this book, you’ll be able to deal with complex data problems using unsupervised ML algorithms like principal component analysis and k-means clustering.
Table of Contents (23 chapters)
1
Section 1 – Data Cleaning and Machine Learning Algorithms
5
Section 2 – Preprocessing, Feature Selection, and Sampling
9
Section 3 – Modeling Continuous Targets with Supervised Learning
13
Section 4 – Modeling Dichotomous and Multiclass Targets with Supervised Learning
19
Section 5 – Clustering and Dimensionality Reduction with Unsupervised Learning

Chapter 10: Logistic Regression

In this and the next few chapters, we will explore models for classification. These involve targets with two or several class values, such as whether a student will pass a class or not or whether a customer will choose chicken, beef, or tofu at a restaurant with only these three choices. There are several machine learning algorithms for these kinds of classification problems. We will take a look at some of the most popular ones in this chapter.

Logistic regression has been used to build models with binary targets for decades. Traditionally, it has been used to generate estimates of the impact of an independent variable or variables on the odds of a dichotomous outcome. Since our focus is on prediction, rather than the effect of each feature, we will also explore regularization techniques, such as lasso regression. These techniques can improve the accuracy of our classification predictions. We will also examine strategies for predicting a multiclass...