Paul Jose has a Web site referred to in the section on mediation. He discusses a problem in which he believes that stress leads to depression through a mediating path via rumination.

(In other words, some stressed people ruminate, and as a consequence they become depressed.) The path diagram derived from his analysis of actual data are shown below. The beta given for the path from stress to depression is from the multiple regression of depression on stress and rumination. Predicting depression only from stress had a beta of .471.

Test the decline in the coefficient for the direct path from stress to depression using Sobel’s test. (You can check your work at Jose’s Web site at http://www.victoria.ac.nz/psyc/staff/

paul-jose-files/helpcentre/help7_mediation_example.php, though the answers will not be exactly equal.