Book Image

Bayesian Analysis with Python - Third Edition

By : Osvaldo Martin
Book Image

Bayesian Analysis with Python - Third Edition

By: Osvaldo Martin

Overview of this book

The third edition of Bayesian Analysis with Python serves as an introduction to the main concepts of applied Bayesian modeling using PyMC, a state-of-the-art probabilistic programming library, and other libraries that support and facilitate modeling like ArviZ, for exploratory analysis of Bayesian models; Bambi, for flexible and easy hierarchical linear modeling; PreliZ, for prior elicitation; PyMC-BART, for flexible non-parametric regression; and Kulprit, for variable selection. In this updated edition, a brief and conceptual introduction to probability theory enhances your learning journey by introducing new topics like Bayesian additive regression trees (BART), featuring updated examples. Refined explanations, informed by feedback and experience from previous editions, underscore the book's emphasis on Bayesian statistics. You will explore various models, including hierarchical models, generalized linear models for regression and classification, mixture models, Gaussian processes, and BART, using synthetic and real datasets. By the end of this book, you will possess a functional understanding of probabilistic modeling, enabling you to design and implement Bayesian models for your data science challenges. You'll be well-prepared to delve into more advanced material or specialized statistical modeling if the need arises.
Table of Contents (15 chapters)
Preface
12
Bibliography
13
Other Books You May Enjoy
14
Index

6.6 Categorical predictors

A categorical variable represents distinct groups or categories that can take on a limited set of values from those categories. These values are typically labels or names that don’t possess numerical significance on their own. Some examples are:

  • Political affiliation: conservative, liberal, or progressive.

  • Sex: female or male.

  • Customer satisfaction level: very unsatisfied, unsatisfied, neutral, satisfied, or very satisfied.

Linear regression models can easily accommodate categorical variables; we just need to encode the categories as numbers. There are a few options to do so. Bambi can easily handle the details for us. The devil is in the interpretation of the results, as we will explore in the next two sections.

6.6.1 Categorical penguins

For the current example, we are going to use the palmerpenguins dataset, Horst et al. [2020], which contains 344 observations of 8 variables. For the moment, we are interested in modeling the mass of the...