Codice 60/2013 Titolo An urn model to construct an efficient test procedure for response adaptive designs Data 2013-11-29 Autore/i Ghiglietti, A.; Paganoni, A.M. Link Download full text Pubblicato Statistical Methods and Applications Abstract We study statistical performance of different tests for comparing the mean effect of two treatments. Given a test T0, we determine which sample size and proportion allocation guarantee to a test T to be better than T0, in terms of (a) higher power and (b) fewer subjects assigned to the inferior treatment. The adoption of a response adaptive design to implement the random allocation procedure is necessary to ensure that both (a) and (b) are satisfied. In particular, we propose to use a Modified Randomly Reinforced Urn design (MRRU) and we show how to perform the model parameters selection for the purpose of this paper. The opportunity of relaxing some assumptions is examined. Results of simulation studies on the test performance are reported and a real case study is analyzed.