"Class" means a position or group of positions, established under the authority of this Title, sufficiently similar in respect to duties, responsibilities and authority thereof, that the same descriptive title may be used to designate each position allocated to the class; that essentially similar requirements as education, experience, ability and other qualifications should be required of the incumbents; that similar tests of fitness may be used to choose qualified employees; and that similar schedules of compensation can be made to apply with equity.