Lesson 3.5 – Sampling and Surveys

  • Explain how undercoverage can lead to bias. 
  • Explain how nonresponse can lead to bias.
  • Explain how other aspects of a sample survey can lead to bias.

 

Activity: What is wrong with these surveys?

Students have plenty of prior knowledge about how to survey well, they just aren’t necessarily aware of it.  For the most part, students can intuitively identify problems with surveys.  Often, good sampling and survey methods are really just good common sense.  We gave students three different examples of surveys that all had something wrong.  Students discussed in their groups what the issues were and what impact it would have on the results.  After the groups, have worked through the activity, go back through and add the proper vocabulary.  For example, students should identify that conducting a survey via landline phone calls is problematic, this is an example of undercoverage.

 

Notes

Students confused nonresponse with voluntary response bias.  Be sure to clarify with distinct examples of each.

*Voluntary response bias is when an invitation to be part of a survey is given and people decided whether or not to participate.  They were NOT specifically chosen by the researchers.

*Nonresponse is when people ARE chosen by the researchers for the survey but the people do not complete the survey.

 

Bonus: If you have time, try the online only Bonus Lesson 3.5A: Other Random Sampling Methods.  This is a great lesson to use The River Problem.

 

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