Machine learning has definitely been one of the most talked about fields in recent years, and for good reason. Every day new applications and models are discovered, and researchers around the world announce impressive advances in the quality of results on a daily basis.

Each day, many new practitioners decide to take courses and search for introductory materials so they can employ these newly available techniques that will improve their applications. But in many cases, the whole corpus of machine learning, as normally explained in the literature, requires a good understanding of mathematical concepts as a prerequisite, thus imposing a high bar for programmers who typically have good algorithmic skills but are less familiar with higher mathematical concepts.

This first chapter will be a general introduction to the field, covering the main study areas of machine learning, and will offer an overview of the basic statistics, probability, and calculus, accompanied by source code examples in a way that allows you to experiment with the provided formulas and parameters.

In this first chapter, you will learn the following topics:

- What is machine learning?
- Machine learning areas
- Elements of statistics and probability
- Elements of calculus

The world around us provides huge amounts of data. At a basic level, we are continually acquiring and learning from text, image, sound, and other types of information surrounding us. The availability of data, then, is the first step in the process of acquiring the skills to perform a task.

A myriad of computing devices around the world collect and store an overwhelming amount of information that is image-, video-, and text-based. So, the raw material for learning is clearly abundant, and it's available in a format that a computer can deal with.

That's the starting point for the rise of the discipline discussed in this book: the study of techniques and methods allowing computers to learn from data without being explicitly programmed.

A more formal definition of machine learning, from *Tom Mitchell*, is as follows:

This definition is complete, and reinstates the elements that play a role in every machine learning project: the task to perform, the successive experiments, and a clear and appropriate performance measure. In simpler words, we have a program that improves how it performs a task based on experience and guided by a certain criterion.