condition mean min max ZT0-3 1.28247619 0.721805672 1.843146708 ZT4-7 5.05951333975 4.382416941500001 5.736609737999999 ZT8-11 6.9752602897500005 5.992570176 7.9579504035 ZT12-15 6.197653679 5.5245626445 6.8707447135 ZT16-19 5.3985725855 4.8601929715 5.9369521995 ZT20-23 7.447131483000001 6.9492297225 7.945033243500001