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

KNN for binary classification

The KNN algorithm has some of the same advantages as the decision tree algorithm. No prior assumptions about the distribution of features or residuals have to be met. It is a suitable algorithm for the heart disease model we tried to build in the last two chapters. The dataset is not very large (30,000 observations) and does not have too many features.

Note

The heart disease dataset is available for public download at https://www.kaggle.com/datasets/kamilpytlak/personal-key-indicators-of-heart-disease. It is derived from the United States Center for Disease Control survey data on more than 400,000 individuals from 2020. I have randomly sampled 30,000 observations from this dataset for the analysis in this section. Data columns include whether respondents ever had heart disease, body mass index, smoking history, heavy alcohol drinking, age, diabetes, and kidney disease.

Let’s get started with our model:

  1. First, we must load some of...