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

Summary

This chapter introduced key model evaluation measures and techniques so that they will be familiar when we make extensive use of them, and extend them, in the remaining chapters of this book. We examined the very different approaches to evaluation for classification and regression models. We also explored how to use visualizations to improve our analysis of our predictions. Finally, we used pipelines and cross-validation to get reliable estimates of model performance.

I hope this chapter also gave you a chance to get used to the general approach of this book going forward. Although a large number of algorithms will be discussed in the remaining chapters, we will continue to surface the Preprocessing issues we have discussed in the first few chapters. We will discuss the core concepts of each algorithm, of course. But, in a true hands-on fashion, we will also deal with the messiness of real-world data. Each chapter will go from relatively raw data to feature engineering to...