2. Statistics foundations

This chapter introduces key ideas that will support everything you learn in this course and throughout the rest of this textbook.

Some of this material may feel familiar from previous courses, while other concepts may be new. The goal of this chapter is not to master everything at once, but to build a strong foundation you can return to as needed.

How to Use This Chapter

This chapter is organized into short sections that introduce foundational concepts and terminology.

You are not expected to memorize everything right away. Instead, focus on understanding the big ideas and use this chapter as a resource you can revisit throughout the course.

What You’ll Learn

By working through this chapter, you will begin to to:

  • Understand how data are used to answer research questions
  • Distinguish between describing data and making inferences
  • Recognize different types of variables
  • Become familiar with key statistical terms used throughout the course

Chapter Sections

  • 2.1 Describing Our Data:Introduces what data are, how we summarize them, and why descriptive statistics matter.

  • 2.2 Levels of Measurement: Explains different types of variables and how they influence the analyses we choose.

  • 2.3 Descriptive vs Inferential Statistics: Builds the conceptual foundation for hypothesis testing and statistical inference.

  • 2.4 Key Terms & Concepts: Provides definitions and explanations of statistical terms you will encounter throughout the textbook. You do not need to memorize all of these now—return to this section as needed.

Why This Matters

These foundational ideas will be used throughout the rest of the textbook and in your work as a researcher or practitioner.

For example:

  • You will use types of variables to determine which statistical test to run
  • You will use descriptive statistics to summarize and interpret data
  • You will use these concepts to understand hypothesis testing and draw conclusions from data
  • You will rely on key terms and concepts when interpreting output and writing results in APA style

You do not need to master all of this immediately—these ideas will become clearer as you apply them in later chapters.

A Note on Learning Statistics

It’s completely normal if some of these concepts feel challenging or unfamiliar at first. Statistics builds over time, and you will revisit many of these ideas in later chapters with more context and examples.

Focus on understanding the big picture—you will have many opportunities to practice and apply these concepts as you move forward.