At the trial the court shall determine whether the board has acted within its discretion and has correctly construed and applied the law. If it finds that it has, the findings and decision of the board shall be affirmed; otherwise it shall be reversed or modified. The judgment of the court may change, confirm, correct, or modify the values of the property in question as shown upon the roll, and a certified copy thereof shall be filed with the county auditor, who shall change, modify or correct as and if required.