Assuming that the following create a disparate impact based on a protected trait, at least under some circumstances, what problems might an employer have in establishing that the practice is job-related and consistent with business necessity?

• A large employer has jobs open for janitors, administrative assistants, factory workers, engineers, and management. It requires all employees to possess at least two years of college education to be hired.
• Same as (1), except the employer instead has a minimum requirement of a high-school education.
• An employer will not hire any individual who has been convicted of a crime.
• An airline has a requirement that all employees who fly on aircraft have a weight proportional to their height. The requirement is necessary in order for the airline to reduce fuel costs by minimizing the weight it carries on each flight. Female employees are required to fall within the low end of the weight range for their height. Men can fall within the low or medium range of weight for their height.