The method of paired comparisons may be regarded as a special rank order technique. It is a method long used in psychological experimentation and is well adapted to sensory difference testing. This study deals with estimation and testing of the parameters of the Rao-Kupper (1967) model for paired comparisons which allows for tied observations in paired comparison experiments using informative prior. An elicitation of the hyper parameters is carried out. Predictive probabilities that one treatment would be preferred to other treatment in a future single comparison are determined. Graphs for the marginal posterior densities are presented. All calculations are based on numerical integration technique and Gibbs sampling procedure. Appropriateness of the model is checked which declares it a good fit.