condition mean min max ZT0-3 1.7584473333333335 0.817027 2.2544500000000003 ZT4-7 2.338005 2.338005 2.338005 ZT8-11 1.67117 1.67117 1.67117 ZT12-15 1.47448575 0.9840915 1.96488 ZT16-19 3.1748450000000004 3.1748450000000004 3.1748450000000004 ZT20-23 2.611165 2.611165 2.611165