The ideas in this paper are based on an analysis of statistical explanation that uses the information transmitted by a theory. Consider a theory that specifies a probability distribution on the events of some domain, where for purposes of analysis we divide the variables that describe the domain into two sets: [M], a set of variables whose values are to be explained, and [S], a set of variables whose values are used to explain the values of the variables in [M]. The information transmitted by the theory is

(1)

where H(S) and H(M) are the uncertainties of the events in [S] and [M], respectively, and H(S x M) is the uncertainty of the joint events.

To illustrate this idea, consider the problem of explaining medical symptoms such as fever, coughing, skin rash and abdominal pain.