condition mean min max ZT0-3 12.344586666666666 7.60671 15.7649 ZT4-7 8.420639999999999 8.420639999999999 8.420639999999999 ZT8-11 8.36093 8.36093 8.36093 ZT12-15 13.4426 12.2147 14.6705 ZT16-19 12.914950000000001 12.914950000000001 12.914950000000001 ZT20-23 17.9052 17.9052 17.9052