condition mean min max ZT0-3 22.618375 21.6015 23.63525 ZT4-7 25.40285 25.40285 25.40285 ZT8-11 24.5514 24.5514 24.5514 ZT12-15 0 0 0 ZT16-19 23.199550000000002 23.199550000000002 23.199550000000002 ZT20-23 21.84915 21.84915 21.84915