Estimated Lesson Duration:

1-2 class periods



How confident are you that a number will fall within a certain range? Explore confidence intervals with your students! Great for data or election polls! Created for advanced placement (AP) statistics classes.

This lesson is designed to introduce students to the concept of confidence intervals for sample means and the reason for the sample size requirement when data is not normally distributed. The exercise uses data from the “Let’s Get Healthy” health fairs conducted in 2010-2011 school year from nine middle schools from eight school districts. The exercise is designed so that individual students take small (n=10) and large (n=35) random samples from either the female or male population, generate confidence intervals for population means from the samples, provide a class plot of the confidence intervals compared to the known population mean and then compare the results of the two sample sizes in relation to the generated intervals containing the true population mean for these skewed populations.


Key Concepts and Standards:

 Key Concepts: Confidence intervals, population mean, data, random sample, generate, class plot, statistics

Standards: Covers several Common Core State Standards in Statistics and Probability


Preparations/ Materials

• “Let’s Get Healthy” Statistics lesson plan.

• TI-83, 84, or Inspire calculator.

• Figure 1. BMI distribution graph.

• Excel File – “LGH Statistics Exercise Data”

• Either computers with Excel to access Excel files or printouts of the Female and Male BMI pages included with this document


Downloadable Lesson and Supporting Materials

Lesson Plans

  • Confidence Intervals Lesson (.doc)
  • Data for Confidence Intervals lesson  (.xls)

Note: The SeeIt feature of the Let’s Get Healthy! website enables visualization of data sampling and other statistical features!  The link takes you to the help page where you can learn all about it!