condition mean min max ZT0-3 8.933356666666667 6.4381900000000005 10.362545 ZT4-7 5.281485 5.281485 5.281485 ZT8-11 3.9208600000000002 3.9208600000000002 3.9208600000000002 ZT12-15 5.7675875 5.61481 5.920365 ZT16-19 6.8151 6.8151 6.8151 ZT20-23 9.10582 9.10582 9.10582