There are several options available in drawing the plots (available from the menu). These include the option of drawing "2%", "5%", "10%", or "Logarithmic" contour plots, "smoothed" or not, and "outliers" or not. Contrary to the belief of many people, smoothing does not alter the data nor does it distort it. Thus, it is by default left on. Note that turning smoothing off can cause the program to take much longer to draw the plots. "Show Outliers" controls whether events falling outside of the lowest contour are drawn with dots--thus, combining the best advantages of dot plots (revealing low-frequency data) with the best of contour plots (allow high-frequency data to be accurately displayed). 2%, 5% and 10% plots have 50, 20, and 10 contour lines (respectively) that are distributed so that the same number of cells fall between each pair of contour lines. Logarithmic plots distribute the contour levels logarithmically in height; each contour line encloses twice as many events as the previous.

The first set of graphs below compares the same data using different contouring thresholds. The second set of graphs compares 5% probability plots with different options.

You may view a comparison of all the bivariate displays for this same data.