p. 217 - 225 STATISTICAL METHOD OF ASSIGNING FIDUCIDAL LIMITS TO A PROTECTIVE EFFECT ESTIMATED FROM BIOLOGICAL ASSAYS WHICH COMPARE THREE GROUPS OF RESULTS M. Siminovici, A.I. Molnar, N. Bonciocat Chemical-Pharmaceutical Research Institute Bucuresti, 4, Vitan 112 Abstract A statistical method of assigning fiducidal limits to a protective effect is proposed. The method is based on a theorem of mathemartical statistics given by Fieller, and may be applied to all experimental procedures which measure an adequate quantitative response in three groups of animals: intoxicated animals, intoxicated and treated animals, and control animals. A numerical example of assigning fiducidal limits to the antilipical effect of the mucopolysaccharide extracted from Mytilus galloprovincialis in the intoxication with Triton, is also given.