In this paper, we present a model and its evaluation for expressing attitudes through sequences of non-verbal signals for Embodied Conversational Agents. To build our model, a corpus of job interviews has been annotated at two levels: the non-verbal behavior of the recruiters as well as their expressed attitudes was annotated. Using a sequence mining method, sequences of non-verbal signals characterizing different interpersonal attitudes were automatically extracted from the corpus. From this data, a probabilistic graphical model was built. The probabilistic model is used to select the most appropriate sequences of non-verbal signals that an ECA should display to convey a particular attitude. The results of a perceptive evaluation of sequences generated by the model show that such a model can be used to express interpersonal attitudes.