Here are two applets that I created to help you visualize the normal distribution. The first applet shows how the graph changes given a different mean and/or standard deviation. The shape is of course always a 'bell curve'. The second applet is better suited if you want to look at probabilities with data that is normally distributed. Notice how the function that generates this curve contains both pi as well as the natural base, e. The importance of these numbers cannot be underestimated.
