The invention relates to a method of determining a true signal of an analyte, comprising (a) measuring an observed signal x for one or more analytes, and (b) determining a mean signal (.mu.) and a system parameter (.beta.) for said analyte that produce enhanced values for a probability likelihood of said observed signal, said observed signal being related to said mean signal by an additive error (.delta.) and a multiplicative error (.epsilon.), wherein said system parameter specifies properties of said additive error (.delta.) and said multiplicative error (.epsilon.).
 This invention was made with government support under grant number T32 HG 000-35 awarded by the National Institutes of Health and grant number DE-FG03-98ER62652/A000 awarded by the United States Department of Energy. The United States Government has certain rights in this invention.