Book Image

Essential Statistics for Non-STEM Data Analysts

By : Rongpeng Li
Book Image

Essential Statistics for Non-STEM Data Analysts

By: Rongpeng Li

Overview of this book

Statistics remain the backbone of modern analysis tasks, helping you to interpret the results produced by data science pipelines. This book is a detailed guide covering the math and various statistical methods required for undertaking data science tasks. The book starts by showing you how to preprocess data and inspect distributions and correlations from a statistical perspective. You’ll then get to grips with the fundamentals of statistical analysis and apply its concepts to real-world datasets. As you advance, you’ll find out how statistical concepts emerge from different stages of data science pipelines, understand the summary of datasets in the language of statistics, and use it to build a solid foundation for robust data products such as explanatory models and predictive models. Once you’ve uncovered the working mechanism of data science algorithms, you’ll cover essential concepts for efficient data collection, cleaning, mining, visualization, and analysis. Finally, you’ll implement statistical methods in key machine learning tasks such as classification, regression, tree-based methods, and ensemble learning. By the end of this Essential Statistics for Non-STEM Data Analysts book, you’ll have learned how to build and present a self-contained, statistics-backed data product to meet your business goals.
Table of Contents (19 chapters)
1
Section 1: Getting Started with Statistics for Data Science
5
Section 2: Essentials of Statistical Analysis
10
Section 3: Statistics for Machine Learning
15
Section 4: Appendix

Building a naïve Bayes classifier from scratch

In this section, we will study one of the most classic and important classification algorithms, the naïve Bayes classification. We covered Bayes' theorem in previous chapters several times, but now is a good time to revisit its form.

Suppose A and B are two random events; the following relationship holds as long as P(B) ≠ 0:

Some terminologies to review: P(A|B) is called the posterior probability as it is the probability of event A after knowing the outcome of event B. P(A), on another hand, is called the prior probability because it contains no information about event B.

Simply put, the idea of the Bayes classifier is to set the classification category variable as our A and the features (there can be many of them) as our B. We predict the classification results as posterior probabilities.

Then why the naïve Bayes classifier? The naïve Bayes classifier assumes that different features are...