condition mean min max ZT0-3 1.5203936666666666 0.8777860000000001 1.893585 ZT4-7 0.951565 0.951565 0.951565 ZT8-11 1.32232 1.32232 1.32232 ZT12-15 3.926515 3.5508100000000002 4.30222 ZT16-19 4.659929999999999 4.659929999999999 4.659929999999999 ZT20-23 2.934505 2.934505 2.934505