In the RAND study, two plans had full coverage for spending within the hospital, but one had a $150 deductible for ambulatory care. The plan with the ambulatory care deductible had a lower probability of hospital admission (0.115) per year than did the plan with full coverage for everything (0.128), even though both plans covered hospital care fully.(See Table 5.4.) What does this tell you about the use of hospital and ambulatory care? Are they substitutes or complements? Explain how this happens in plain English, without resorting to fancy economic jargon.