condition mean min max ZT0-3 20.93835 20.93835 20.93835 ZT4-7 18.2575 18.2575 18.2575 ZT8-11 11.34045 11.34045 11.34045 ZT12-15 12.7837 12.7837 12.7837 ZT16-19 16.779200000000003 16.779200000000003 16.779200000000003 ZT20-23 20.981949999999998 20.981949999999998 20.981949999999998