CCSS.Math.Content.8.SP.A.4
The standard
Understand that patterns of association can also be seen in bivariate categorical data by displaying frequencies and relative frequencies in a two-way table. Construct and interpret a two-way table summarizing data on two categorical variables collected from the same subjects. Use relative frequencies calculated for rows or columns to describe possible association between the two variables.
Common Core State Standards for Mathematics · Statistics and Probability
What this standard means
Students need to organize data about two yes-or-no or category-based traits from the same people. They should make a two-way table, calculate row or column percentages, and use those percentages to describe whether the traits seem related.
Mastery looks like choosing the right totals, comparing fair percentages, and saying what the data suggests without claiming proof. Students often get stuck using counts instead of relative frequencies, mixing up row and column percentages, or making causal claims from a table.
Ways to teach it
- Have students survey classmates on two categorical questions, then build a two-way table with counts and row percentages on paper.
- Prompt students: Which group has the higher percentage, and what does that suggest about the two categories?
- Give a completed two-way table and ask students to calculate one missing relative frequency and write one comparison sentence.
- Use a school lunch survey, such as packed lunch versus buying lunch and sports participation, to discuss patterns in real data.
Plan a lesson for CCSS.Math.Content.8.SP.A.4
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Related standards
- CCSS.Math.Content.HSS-CP.A.4
Construct and interpret two-way frequency tables of data when two categories are associated with each object being classified. Use the two-way table as a sample...
- CCSS.Math.Content.HSS-ID.B.5
Summarize categorical data for two categories in two-way frequency tables. Interpret relative frequencies in the context of the data (including joint, marginal,...
- CCSS.Math.Content.8.SP.A
Investigate patterns of association in bivariate data.
- CCSS.Math.Content.HSS-ID.B
Summarize, represent, and interpret data on two categorical and quantitative variables