Web-based exercise. One of the best ways to grasp the idea of probability is to watch the proportion of trials on which an outcome occurs gradually settle down at the outcome’s probability. Computer simulations can show this. Go to the Statistics: Concepts and Controversies Web site, www.whfreeman.com/scc7e, and look at the Probability applet.

Select a probability for heads between 0.2 and 0.8 and run the applet for a total of 400 trials. Describe the pattern you see. How quickly did the proportion of heads settle down to the true probability?