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

Section 4 – Modeling Dichotomous and Multiclass Targets with Supervised Learning

There are a good number of high performing algorithms for predicting categorical targets. We will examine the most popular classification algorithms in this part. We will also consider why we might choose one algorithm over any of the others given the attributes our data and our domain knowledge.

We are as concerned with underfitting and overfitting with classification models as we were with regression models in the previous part. When the relationship between features and the target is complicated, we need to use an algorithm that can capture that complexity. But there is often a non-trivial risk of overfitting. We will discuss strategies for modeling complexity without overfitting in the chapters in this part. This usually involves some form of regularization for logistic regression models, limits on tree depth for decision trees, and adjusting the tolerance for margin violations with support...