condition mean min max ZT0-3 14.526266666666666 12.32565 16.94265 ZT4-7 9.08324 9.08324 9.08324 ZT8-11 10.203109999999999 10.203109999999999 10.203109999999999 ZT12-15 23.890825 21.76745 26.014200000000002 ZT16-19 19.157249999999998 19.157249999999998 19.157249999999998 ZT20-23 19.3925 19.3925 19.3925