condition mean min max ZT0-3 7.01508 7.01508 7.01508 ZT4-7 7.40577 7.40577 7.40577 ZT8-11 5.08554 5.08554 5.08554 ZT12-15 5.1518999999999995 5.1518999999999995 5.1518999999999995 ZT16-19 5.57972 5.57972 5.57972 ZT20-23 6.496575 6.496575 6.496575