Variables are:
zip: 'character': Postal code.
hid: 'character': Hospital ID.
city: 'character': Hospital city.
state: 'character': Hospital state.
tot_sales: 'numeric': Total sales to hospital.
tot_knee: 'numeric': Number of knee operations.
tot_hip: 'numeric': Number of hip operations.
beds: 'numeric': Number of beds.
rehab_beds: 'numeric': Number of beds dedicated for rehabilitation.
outpatient_visits: 'numeric': Number of outpatient visits.
adm_costs: 'numeric': Administrative costs ($1000's / yr).
revenue_inpatient: 'numeric': Inpatient revenue.
is_teaching: 'numeric': Is teaching hospital?
has_trauma: 'numeric': Has trauma center?
has_rehab: 'numeric': Offers rehabilitation?