condition mean min max ZT0-3 2.1200950067499997 1.846806661 2.3933833525 ZT4-7 3.015371921 2.4686769259999997 3.562066916 ZT8-11 5.84840991525 4.436442399 7.2603774315 ZT12-15 6.466797881250001 5.0687305595000005 7.864865203 ZT16-19 6.91707073175 6.8978369645 6.936304499 ZT20-23 8.82514551075 8.1498759045 9.500415117