condition mean min max ZT0-3 4.8284650000000005 3.63582 5.94414 ZT4-7 3.197295 3.197295 3.197295 ZT8-11 2.740335 2.740335 2.740335 ZT12-15 4.08916 4.017975 4.1603449999999995 ZT16-19 5.041265 5.041265 5.041265 ZT20-23 6.369730000000001 6.369730000000001 6.369730000000001