condition mean min max ZT0-3 399.687635 399.687635 399.687635 ZT4-7 534.838713 534.838713 534.838713 ZT8-11 849.6858460000001 849.6858460000001 849.6858460000001 ZT12-15 930.0275915 930.0275915 930.0275915 ZT16-19 914.8638875 914.8638875 914.8638875 ZT20-23 789.355671 789.355671 789.355671