Problems of the randomization test for AB designs

N = 1 designs imply repeated registrations of the behaviour of the same experimental unit and the measurements obtained are often few due to time limitations, while they are also likely to be sequentially dependent. The analytical techniques needed to enhance statistical and clinical decision making have to deal with these problems. Different procedures for analysing data from single-case AB designs are discussed, presenting their main features and revising the results reported by previous studies. Randomization tests represent one of the statistical methods that seemed to perform well in terms of controlling false alarm rates. In the experimental part of the study a new simulation approach is used to test the performance of randomization tests and the results suggest that the technique is not always robust against the violation of the independence assumption. Moreover, sensitivity proved to be generally unacceptably low for series lengths equal to 30 and 40. Considering the evidence available, there does not seem to be an optimal technique for single-case data analysis

El territorio y la ciudad de Tarraco

This paper presents a brief description of the archaeological research in the territory and in the city of Tarraco, the ancient capital of provincia Hispania Tarraconensis and one of the main centres for the spread of Hispanic Christianity. Althoug Tarraco was the last capital under imperial control and the firs Hispanic metropolitan see, the city had only a secondary role by comparison with other Hispanic cities during late antiquity. This evolution shaped the development of Tarraco during the 7th century, but archaeologists identify an important architectural vitality still in the 6th century at the same time as other episcopal cities were evolving. During this period, the final Christianization of the symbolic spaces of ancient paganism took place, establishing the ideological basis of medieval urbanism that is still preserved today. The paper also interprets the sites through raising key questions as well as describing rural settlements, where archaeological knowledge is not so far advanced, due in part to the difficult nature of archaeological research, and in part to the need to study new construcitve models, as well as to the systematic collection of the relevant material culture.