Instructor Guide 2B: Forming Connections

Overview

  • In this in-class activity, students will think more deeply about the relationship between a population and a sample.
  • Students will determine a population and sample based on a research question and identify potential issues with sampling bias.
  • This activity connects back to selecting a random sample and prepares students for drawing conclusions from a sample.
  • S2, C2, C4, V1, V4, 03 ← Link to EBTP descriptions 

Prerequisite assumptions

Students should be able to do each of the following after completing the What to Know assignment.

  • Define sample vs. population.
  • Identify the different sampling methods.

Intended goals for this activity

After completing this activity, students should understand that selection of a representative sample from a population is important for generalizing conclusions on the population. They will be able to identify sampling bias and describe a random and representative sample from a population.

Synchronous Delivery and Activity Flow

The sample activity delivery below assumes a face-to-face class meeting but can be adapted to a fully online or hybrid delivery by using break-out rooms for pairs and small groups.

Frame the activity (3 minutes)

  • Question 1 — think-pair-share S2, C4, V1, V4, O3
    • Allow a minute for students to discuss their answers with a partner.
    • Have a few volunteers share their answers and make sure that the population of interest is clear to all students.
  • Transition to the in-class activity by briefly discussing the Objectives for the activity.

Activity Flow (20 minutes)

  • Have students individually read the text prior to Question 2. Field any questions about sampling bias that come up before continuing.
  • Questions 2 – 5 — working in pairs S2, C4, V1, V4, O3
    • The goal of Questions 2 and 3 is to have students identify sources of bias.
    • Check in with the pairs after Question 3 to make sure they understand the sources of bias.
    • The goal of Question 4 is to connect what students have learned about sampling in previous activities with the new sampling methods introduced in the preview assignment.
    • Debrief Question 4 carefully with the whole class. The sample answer revolves around taking a stratified sample, but take time to discuss how simple random samples, systemic sampling, and convenience sampling may or may not be appropriate.

Wrap-up/transition (5 minutes)

  • Wrap-up the activity by having pairs share their answers to Question 5. As much as possible during discussion, take the opportunity to include the following:
    • Sampling methods – simple random sampling, systematic sampling, stratified sampling, convenience sampling
    • Sources of bias – undercoverage, non-response bias, response bias, voluntary response bias
    • Have students refer back to the Objectives for the activity and check the ones they recognize. Alternatively, they may check the objectives throughout the activity.
  • Let students know that in the next activity they will explore the idea of experimental design.
  • Assign the homework or Practice and any What to Know pages for the Forming Connections activities you plan to complete in the next class meeting. C2