condition mean min max ZT0-3 16.729799999999997 15.906600000000001 17.552999999999997 ZT4-7 15.13545 15.13545 15.13545 ZT8-11 25.0674 25.0674 25.0674 ZT12-15 0 0 0 ZT16-19 31.21515 31.21515 31.21515 ZT20-23 24.679450000000003 24.679450000000003 24.679450000000003