This applet lets you see how the results of an experiment with a lot of trials might look. Experiment with moving the standard deviation lines to change the shape of the graph. Try to answer these questions:

• What is related about the standard deviation and the shape of the graph? What moves with the standard deviation lines? (hint: look at whether the graph is curving concave-up, like a right-side-up spoon, or concave-down)
• Does the area below the curve seem to change when the standard deviation gets bigger or smaller?
• Create a histogram with 100 trials. Experiment with the bin size. Does the histogram look like it fits the curve well? Does it depend on bin size? Does it help more to have bigger or smaller bins?
• Try the same experiment with 1000 trials, then 5000. Is the normal curve approximation more accurate for large or small samples?
• If you had only ten trials, do you think you would be likely to get a nice, smooth normal distribution?