Sec. 5. As used in this chapter, "state agency" means an authority, board, branch, commission, committee, department, division, or other instrumentality of any of the following:
(1) The executive, including the administrative department of state government.
(2) The legislative department of state government.
(3) The judicial department of state government.
(4) A state educational institution.
(5) A body corporate and politic created by statute.