New Confidence Interval Applet

The new applet running below is designed to help students understand confidence intervals. Each of the 50 lines on the graph below represents a confidence interval for the mean (assuming known variance). Each interval is based on a sample of size 5 taken from a standard normal distribution (mean=0 and variance=1). By changing alpha, students can see how the confidence intervals are affected by this parameter. Also, students get a good idea of what a confidence interval really means in terms of covering the true mean. Students should be encouraged to reload the applet several times and keep a running count of the coverage probability for a given value of alpha.