Classical likelihood theory
It is clear that these two classes refer to statistical modelling and inference. In the same paper, for the ﬁrst time, Fisher coined the term ‘likelihood’ explicitly and contrasted it with ‘probability’, two “radically distinct concepts [that] have been confused under the name of ‘probability’...”. Likelihood is a key concept in both modelling and inference, and throughout this book we shall rely greatly on this concept. This chapter summarizes all the classical likelihood concepts from Pawitan (2001) that we shall need in this book; occasionally, for more details, we refer the reader to that book.