Surfstat.australia: an online text in introductory Statistics

Java applet hotlist

To explore these interactive tools you will need a Web browser capable of running Java (unfortunately not Netscape for Windows 3.1).

Click on the picture to jump to the applet.

Centres

This applet lets you play around with data to see how the mean and median respond.

Growing histograms

This applet lets you watch as data are sampled from the Normal distribution. Large samples give a good impression of the shape of the distribution, while small samples illustrate sample-to-sample variation. You can explore the effect of changing the parameters of the normal distribution, and experiment with how many bins are appropriate for different sample sizes.

Linear regression

Here, you can add and relocate X-Y data-points and see how the least squares regression line changes to fit them. The correlation in your data is displayed, and the equation of the line. If you wish, you can add confidence limits around the line.

Discrete probability distributions

The normal distribution is a good approximation to the Binomial and Poisson distributions - sometimes. This applet lets you experiment to find out when. Your choice of discrete distribution is displayed together with the best normal approximation, and you can select numeric intervals to see how the exact and approximate probabilities compare.


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