Wyoming Math 7.SP.1

7.SP.1 is a cluster heading. These are the individual standards under it.

• 7.SP.1a

  Understand that a sample is a subset of a population.

• 7.SP.1b

  Differentiate between random and non-random sampling.

• 7.SP.1c

  Understand that generalizations from a sample are valid only if the sample is representative of the population.

• 7.SP.1d

  Understand that random sampling is used to gather a representative sample and tends to support valid inferences about the population.

01

What Students Need to Do

Students identify the full group being studied and the smaller group surveyed. They decide whether the selection method is random and whether the results can reasonably describe the full group.

02

What Mastery Looks Like

Given a school survey plan, students name the population and sample and identify who might be missed. They propose using a random number generator to select students from a roster. They know one random sample may still differ from the full group.

03

Common Misconceptions

Students may call a survey random because names were picked from whoever was nearby. They may think a large group of volunteers represents everyone, or that a random sample must match the full group exactly.

04

How to Assess It

A school wants to know how seventh graders get to school, so it asks the first 20 students off a bus. Name the population and sample, explain the problem with this choice, and describe how to select 20 students randomly.

1. 01

   Fill a bag with 30 red and 10 blue counters; have students draw 10 without looking and compare their estimate with the actual mix.

2. 02

   Ask students to explain why surveying only basketball players cannot estimate how many seventh graders play sports.

3. 03

   Give pairs six survey plans to sort as random or non-random, then have them defend one choice by naming who might be missed.

4. 04

   Show two survey cards, '40 weekend park visitors' and '40 randomly chosen households'; ask which better estimates citywide park use and why.

• 7.RP.3

  Solve multi-step real-world and mathematical problems involving ratios and percentages.

• 7.G.6

  Solve real-world and mathematical problems involving:

• 8.F.4

  Apply the concepts of linear functions to real-world and mathematical situations.