ABSTRACT
In pharmacology and toxicology experiments three or more than three treatment groups are usually used. One of the objectives for carrying out the experiment with three or more than three groups is to assess the dose-dependency of the test substance. Dose-dependency is an important concept for evaluating toxicological data (Hamada et al., 1997). In order to examine whether the change in a parameter observed in a study is dosedependent, a trend test is used. A trend test examines whether the results in all dose groups together increase as the dose increases (EPA, 2005). Trend tests have been recommended as a customary method for analyzing data from subchronic and chronic animal studies (Selwyn, 1995). For examining quantitative data, Jonckheere’s trend test (Jonckheere, 1954) is generally used. The frequency data are examined by Cochran-Armitage trend test (Cochran, 1954; Armitage, 1955).
