Abstract: | Starting from N paired differences of a continuous variable, BENNETT 's (1962) bivariate sign test is identified as a test against so called homeopoetic treatment effects (or location shifts in one or both variables X and Y). As a complement, a new sign test is identified to be sensitive to so called heteropoetic treatment effects (shifts in dispersion). Both tests are shown to be important in biomedical and psychosocial research. A numerical example is given from psychopharmacology using the new bivariate sign test. |