Sampling Distribution of the Variance

This applet allows exploration of the effects of sample size on the sampling distributions of the sample variance.

Instructions

  1. Use the menus above the two bottom graphs to select sample sizes to be compared.
  2. Click on the "1 Sample" button to see each new sample added to the graph. After you understand the process, click on the "1000 Samples" button to add 1000 samples to each graph. Do this many times to build a complete sampling distribution for the variance.
  3. Click on the "Toggle Theory" button to turn display the theoretical distribution, which is proportional to the chi-squared distribution, on or off.
  4. Clicking on a graph pops it up in a separate window. This faciliates comparisons among the graphs. For exampe, clicking on the two bottom graphs allows you to align them in a vertical stack to see the differences in their spreads.