Mississippi Math 7.SP.4

Math7th GradeStatistics and Probability (SP) Use Random Sampling to Draw Inferences About a Population

The Standard

Use measures of center and measures of variability (i.e., inter-quartile range) for numerical data from random samples to draw informal comparative inferences about two populations. For example, decide whether the words in a chapter of a seventh-grade science book are generally longer than the words in a chapter of a fourth-grade science book.

2025 Mississippi College- and Career-Readiness Standards for Mathematics · Draw Informal Comparative Inferences about Two Populations

Teacher's field guide

What This Standard Means

What Students Need to Do: Students find the median and interquartile range (IQR) for random samples from two groups. They use both measures to compare what is typical and how much the values vary.
What Mastery Looks Like: A student calculates both medians and IQRs correctly. They explain whether the difference in medians is large compared with the spread, without claiming that every member of one group has a higher value.
Common Misconceptions: Students may subtract the smallest value from the largest and call it the IQR. They may find quartiles before sorting the data or use one extreme value to judge an entire group.
How to Assess It: Exit ticket: Eight randomly sampled bus rides per route, in minutes, are A: 12, 13, 13, 14, 14, 15, 15, 16 and B: 15, 16, 16, 17, 17, 18, 18, 19. Find each median and IQR, then explain which route usually takes longer.

Lesson moves

Ways to Teach It

Make two bags with cards 2 to 11 and 5 to 14; pairs draw five from each and compare medians and IQRs.
Write why A: 2, 4, 4, 4, 6, 6, 6, 8 and B: 0, 0, 0, 4, 6, 10, 10, 10 have the same median but different IQRs.
Race to match sample cards A: 1, 2, 3, 4, 5, 6, 7, 8 and B: 4, 5, 6, 7, 8, 9, 10, 11 to median, IQR, and comparison cards.
Randomly choose eight sandwich prices from each of two local cafe menus; compare medians and IQRs before ordering lunch.

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