Experience 10 - Confidence Intervals for Proportions

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Confidence Intervals for Proportions



Now we will learn how to estimate a population proportion with a sample proportion. The procedure mirrors that for the mean and you will want to review the calculations for the mean and standard deviation of a binomial distribution to make sense of the clever use of the central limit theorem that our author presents. Again, we will be able to create logical estimates and judge the credulity of those made by others. Chances are you will be exposed to some abuse of these techniques before the year is over and now you will have the tools needed to refute it. 

Learning Objectives

  • Know how to determine and interpret a confidence interval for a proportion
  • Understand the roles of sample size, confidence level, and spread on the margin of error.

Performance Criteria

  • The learner will calculate confidence intervals for the proportion using technology accurate to 2 decimal places.
  • The learner will interpret confidence intervals for the proportion using a complete sentence that includes the confidence level.
  • The learner will determine the sample size necessary for a desired margin of error.
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Chapter 8 (This is a video by the authors covering chapter 8. Just watch the parts relating to section 8.3)

Confidence Intervals for the Proportion (TI-84)

Confidence Intervals for the Proportion (Excel)

Click on "Textbook" to view the assigned reading or read Section 8.3 from your print or digital copy.

See Example 3 for the problems in this experience.

Confidence Interval Flow Chart

If you find a better online tool then please send me the link


  1. Review - Read the above components and post any questions in the forum below. 
  2. Practice - Complete the practice exercises that follow.
  3. Think - Answer the Critical Thinking questions in the "Critical Thinking" forum. 
  4. Apply - Complete the Application Problems and upload your completed file
  5. Assess - Complete the Mid-Term Assessment for this Experience.

If you have any questions about the content (readings, problems, etc.) then post in the "Questions about Experience 10" forum. 

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Practice Problem Videos

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