In this Chapter, we discuss the speciﬁcation of the form of the prior distributions for our parameters which we are using to quantify our available prior knowledge. We can specify any prior distribution that we like but our choice is guided by the range of values of the parameters. For example, the probability of success in a Binomial experiment has (0,1)
as its range of possible values, the mean of a Normal distribution has (−∞,+∞) as its range of values, and the variance of a Normal distribution has (0,+∞) as its range of values. There are three common types of prior distributions.