For the purposes of this act:
(a) "Appraisal foundation" and "foundation" mean the appraisal foundation established on November 30, 1987, as a not-for-profit corporation under the laws of Illinois.
(b) "Written appraisal" means a written statement used in connection with the activities of the division of property valuation or a county appraiser that is independently and impartially prepared by a county appraiser setting forth an opinion of defined value of an adequately described property as of a specific date, supported by presentation and analysis of relevant market information.