condition mean min max ZT0-3 3.352593333333333 1.96727 4.424325 ZT4-7 1.406435 1.406435 1.406435 ZT8-11 2.9296949999999997 2.9296949999999997 2.9296949999999997 ZT12-15 3.990435 3.8620200000000002 4.11885 ZT16-19 4.1353 4.1353 4.1353 ZT20-23 5.3735 5.3735 5.3735