condition mean min max ZT0-3 2.9321675 2.596825 3.2675099999999997 ZT4-7 4.5472 4.5472 4.5472 ZT8-11 9.42735 9.42735 9.42735 ZT12-15 0 0 0 ZT16-19 8.723655 8.723655 8.723655 ZT20-23 6.023625 6.023625 6.023625