Ratios of linear combinations in the general linear model

We consider the problem of estimating. the ratio of two linear combinations of thevector of parameters in the general linear model. The nonexistence of an unbiased estimator under normal errorsisdiscussed. Properties of an often used estimator, the maximum likelihood estimator under normal errors, are presented, This is done both for fixed sample size and asymptotically, in the

presence of normal and non-normal errors.