CCSS.Math.Content.HSS-ID.A.3

MathGrades 9–12Interpreting Categorical and Quantitative Data

The Standard

Interpret differences in shape, center, and spread in the context of the data sets, accounting for possible effects of extreme data points (outliers).

Common Core State Standards for Mathematics

Teacher's field guide

What This Standard Means

What Students Need to Do

Students compare quantitative data sets by examining typical values, variability, symmetry, and skew. They connect those differences to the situation and explain how unusual values may change the results.

What Mastery Looks Like

Given dot plots, histograms, or box plots, students accurately compare typical values, variability, symmetry, and skew. They explain how an extreme value affects the mean, median, range, and overall interpretation in context.

Common Misconceptions

Students may describe only the highest and lowest values instead of the overall distribution. They may assume an outlier always changes the median or that greater spread means a greater center. Some compare graphs without using the data’s context or units.

How to Assess It

Exit ticket: Commute times are A: 8, 9, 9, 10, 10, 11, 11, 12 and B: 8, 9, 9, 10, 10, 11, 11, 30 minutes. Compare their shape, center, and spread, then explain how 30 affects each measure.

Lesson moves

Ways to Teach It

  1. Use sticky notes to build two class dot plots, then move one note far right and record which features change.

  2. Show two histograms of test scores and ask, “Which class was more consistent, and what evidence supports your claim?”

  3. Run a card sort matching data displays with statements about center, spread, skew, and outlier effects.

  4. Compare player salaries from two sports teams, then explain why the mean and median may tell different stories.

Learning progression

Where This Standard Sits

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