condition mean min max ZT0-3 1.8702841666666667 1.629925 2.1106433333333334 ZT4-7 2.39451 2.39451 2.39451 ZT8-11 2.88458 2.88458 2.88458 ZT12-15 3.9596662499999997 3.3158625 4.60347 ZT16-19 2.566145 2.15111 2.98118 ZT20-23 0 0 0