Mode testing via the excess mass estimate

The problem of identifying the number of modal groups manifested in a sampl e of data is of continuing interest and importance in statistical practice. In this paper, we combine features of two current approaches to the mode-t esting problem with some new ideas, to produce a method that provides the d ata analyst with a powerful and flexible way of exploring modality in univa riate data. This approach also provides what appears to be the first satisf actory test of modality for samples of circular data.