Seeing Statistics

Use the scrollbar to change the degree of orgranization in the scatterplot and observe the corresponding changes in the correlation coefficient. Click on the "Change Sign" button to reverse the sign of the correlation and the scatterplot. This example illustrates the use of scrollbars and buttons as well as graphics that are constructed as needed.

Note: This applet will not work unless it is loaded from a server it recognizes. It will not work if the page is loaded from a CD. A working version of this page is available at http://psych.colorado.edu/~mcclella/JavaATI/scat.html

This is an example of a large collection of statistical applets available in the online textbook Seeing Statistics by Gary McClelland. Password protection is temporarily turned off at the Seeing Statistics site, so you may examine all the applets. Simply go to
     http://www.seeingstatistics.com
and click on the "Enter" button. Note that this will transfer to a new website. You may want to examine the other example applets at this ATI Java site before going to Seeing Statistics.

With Optional Regression Line Displayed



With Optional Slope "Votes" Displayed

Each observation "votes" for the best slope. The best slope for a given observation represents a line passing from the centroid to the point. The least-squares regression slope is a weighted average of these individual slope votes with the weight being a function of the observations distance from the mean in the horizontal direction.



With Optional Quadrants Displayed

The stronger the correlaton, the more each observation agrees with respect to being above or below the means of the respective variables. With positive correlations, the observations tend to be either both above the respective means or both below the variable means. Hence, there are more observations in the two quadrants on the positive diagonal. With negative correlations, the observations tend to be above the mean on one variable and below the mean on the other variable. Hence, there are more observations in the two quadrants on the negative diagonal.

HTML and Param tags

Below is sample code to place this applet on an html page. The codebase is specified relative to the html file and does not need to be "../../lib" as below. 

<applet code=com.bolderstats.regcorr.CorrelationPicture.class 
    width="450" height="410" 
    codebase="../../lib" 
    archive="bolderstats_obf.jar,jmsl_obf.jar">
    <param name="LINE" value="TRUE">
</applet>
LINE
Determines whether the least-squares regression line is displayed (TRUE) or not (FALSE, default).
SLOPES
Determines whether the slope "votes" are displayed (TRUE) or not (FALSE, default).
QUADRANTS
Determines whether the quadrants, defined by the means, are displayed (TRUE) or not (FALSE, default).