15. For any 8 which is an interior point of the natural parameter space, the expectations and covariances of the statistics in the exponential family (35) are given by E[~(X)] alog C(8) a~ (j=I, ... ,k), E[T;(X)~(X)] - [ET;(X)E~(X)] = _ a 2 10g C( 8) ----j VVj (i ,j=I,. . . , k ).