Lewis & Clark Community College
MATH 145 (Elementary Statistics)
This module will help students better understand confidence intervals.
Students will use the RandNorm function on the TI-83 graphing calculator
to generate random samples of size 30 from a normal distribution with population mean
µ = 100 and population standard deviation Θ= 20.
The sample mean
will then be calculated
for the random sample and a 0.90 confidence interval will be placed around it. Students will
then determine whether or not the falls within the confidence interval found. This process will
be repeated 20 times. Students will then calculate the percentage of the confidence intervals
that did in fact contain µ = 100. Each student's results will then be grouped with the results
of other students in the class. Students will then calculate the class percentage of the confidence
intervals that actually contained µ = 100. The result should be approximately 90%.
Students are then asked to repeat the process for 0.80 and 0.95 confidence levels.
This module will transfer to any introductory statistics class or any class that discusses confidence levels.