In the previous lesson, students used samples to estimate measures of center of a population. In this lesson, students estimate population proportions. The term proportion is used in statistics to refer to a number from 0 to 1 that represents the fraction of the data belonging to a given category.
Students see that if a sample is representative of the population, then we can use proportional reasoning to make predictions about the population. However, students need to understand that, due to sampling variability, these predictions are estimates, not exact answers like they get when working with actual proportional relationships (MP3).
The activity about examining a distribution of proportions from many different samples is included as an optional opportunity to deepen students' understanding of sampling variability.
Lesson overview
 16.1 Warmup: Getting to School (5 minutes)
 16.2 Activity: Reaction Times (15 minutes)
 16.3 Activity: A New Comic Book Hero (15 minutes)

16.4 Optional Activity: Flying to the Shelves (10 minutes)
 Includes "Are you Ready for More?" extension problem
 Lesson Synthesis
 16.5 Cooldown: More than 48 Grams (5 minutes)
Learning goals:
 Compare (orally) proportions for the same category from different samples of a population.
 Comprehend that the term “proportion” refers to a number between 0 and 1 that represents the fraction of the data within a certain category.
 Use the proportion of a random sample that is within a certain category to make inferences about the population, and explain (orally and in writing) the reasoning.
Learning goals (student facing):
 Let’s estimate population proportions using samples.
Learning targets (student facing):
 I can estimate the proportion of population data that are in a certain category based on a sample.
Required materials:
 preprinted slips, cut from copies of the blackline master
 paper bags
Required preparation:
 Print and cut up slips from the Reaction Times blackline master.
 Prepare one set of slips in a paper bag for every 2 students.
Glossary:
 proportion  A proportion of a data set is the fraction of the data in a given category. For example, a class has 18 students. There are 2 lefthanded students and 16 righthanded students in the class. The proportion of students who are lefthanded is \(\frac{2}{20}\), or 0.1.
 Access the complete Grade 7 glossary.
Standards:
 This lesson builds towards the standards: CCSS.7.SP.A.1MS.7.SP.1MO.7.DSP.A.1bMO.7.DSP.A.1cMO.7.DSP.A.1aCCSS.7.SP.A.2MS.7.SP.2
 This lesson builds towards the standard: CCSS.6.NS.C.7MS.6.NS.7
IM 6–8 Math was originally developed by Open Up Resources and authored by Illustrative Mathematics, and is copyright 20172019 by Open Up Resources. It is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). OUR's 6–8 Math Curriculum is available at https://openupresources.org/mathcurriculum/.
Adaptations and updates to IM 6–8 Math are copyright 2019 by Illustrative Mathematics, and are licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
Adaptations to add additional English language learner supports are copyright 2019 by Open Up Resources, and are licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
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