RECENTLY, a major urban hospital planned to increase and improve its cardiac-care services. The hospital desired an increase in the number of acute coronary-care-unit beds; it also planned to establish an intermediate-care facility so that patients with infarction could be discharged into a unit that provided less care than the acute unit, but more care than the general-hospital beds. Planning required an estimate of the number of beds necessary for both acute and intermediate coronary care.Since the admission of a patient with a suspected acute myocardial infarction is an event that cannot be expected to occur at regularly spaced . . .