As used in this chapter, the term:

(1) "Community services" means all community-based services deemed reasonably necessary by the department to provide for education, training, rehabilitation, and care of mentally retarded individuals and shall include but not be limited to: diagnostic and evaluation services; day-care and training services; work-activity services; community residential services such as group family-care homes; transportation services incidental to educational, training, and rehabilitation services; social services; medical services; and specified home services.

(2) "Mentally retarded individual" means a person whose ability to care for himself is substantially impaired by mental retardation or by a neurological dysfunction associated with mental retardation.

(3) "Mental retardation" means a state of significantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior and originating in the developmental period.