condition mean min max ZT0-3 7.003986666666666 6.709705 7.203374999999999 ZT4-7 15.7913 15.7913 15.7913 ZT8-11 29.40475 29.40475 29.40475 ZT12-15 16.3147 15.283999999999999 17.345399999999998 ZT16-19 13.38825 13.38825 13.38825 ZT20-23 12.0551 12.0551 12.0551