condition mean min max ZT0-3 2.0316056666666666 1.2764069999999998 2.5431299999999997 ZT4-7 1.3889135000000001 1.3889135000000001 1.3889135000000001 ZT8-11 2.4805 2.4805 2.4805 ZT12-15 2.1978075 2.082415 2.3132 ZT16-19 1.80704 1.80704 1.80704 ZT20-23 2.772125 2.772125 2.772125