Chapter 2: Displaying and Summarizing Categorical Data

• Contingency tables organize responses for two categorical variables.
• Marginal distributions help us understand the overall proportions of each category.
• Percentages make it easier to compare trends in different groups.
• Contingency tables are valuable for analyzing relationships in survey data.

Each section follows the same learning progression: understand the concept, practice the skill, think like a statistician, then apply your learning to authentic data.

Whether learning independently or teaching a class, the learning path below is designed to help students master the concepts in this section. Page references below correspond to the Real World Statistics instructional system.

Step 1: Watch the lesson video

Watch the lesson video and take notes on the key ideas.

Step 2: Read the section

Read pages 41-45 to reinforce the concepts introduced in the lesson.

Step 3: Practice what you've learned

Complete the 3 multi-part practice questions on pages 45-46. Check your work using the Answer Key, then review and correct any questions you missed before moving on.

Step 4: Think like a statistician
Explore Enrichment: Role-Based Statistical Analysis Tasks and the Chapter Dataset to apply statistical thinking in real-world contexts.

If you'd like additional guidance while working through the practice questions, explore the Worked Solutions Manual for step-by-step solutions and explanations.

Examples of authentic statistical work supported by this section include:

• organizing two categorical variables into contingency tables (e.g., survey responses on breakfast habits and energy levels, employee hiring records by department and hiring source, or student participation by grade level and activity type) 
• analyzing relationships between categorical variables using marginal distributions and percentages (e.g., customer satisfaction by membership status, transportation method by neighborhood, or volunteer participation by age group) 
• writing evidence-based reports that interpret patterns in contingency tables (e.g., course enrollment by grade level, patient outcomes by treatment type, or voting preference by age group) using proportions to support conclusions

You may use these ideas to design your own investigations or explore the Real World Statistics System.

Enrichment: Role-Based Statistical Analysis Tasks place students in the role of a statistician working on real research problems, where they evaluate data, justify decisions, and communicate findings clearly. Each section includes multiple enrichment tasks, including one with a model response that demonstrates statistical reasoning in context, showing how evidence is evaluated, decisions are justified, and conclusions are communicated. This serves as a bridge to working with authentic datasets and independent statistical investigation within each chapter.

Available in the Interactive eBook at the end of the section (page 46) and in the Appendix of the Print Book (page 401).

Teaching with Real World Statistics: These structured learning paths—including Enrichment tasks and Chapter Datasets—can be adapted or copied directly into Canvas, Google Classroom, Schoology, and other learning management systems to simplify lesson planning and student assignments.