The rules of evidence as applied in a nonjury civil case in a district court of this state shall apply to a contested case except that evidence inadmissible under those rules may be admitted if the evidence is:
(1) necessary to ascertain facts not reasonably susceptible of proof under those rules;
(2) not precluded by statute; and
(3) of a type on which a reasonably prudent person commonly relies in the conduct of the person's affairs.