condition mean min max ZT0-3 4.642398333333333 4.21092 4.94936 ZT4-7 2.6969250000000002 2.6969250000000002 2.6969250000000002 ZT8-11 2.21971 2.21971 2.21971 ZT12-15 3.535825 3.21697 3.85468 ZT16-19 3.2059949999999997 3.2059949999999997 3.2059949999999997 ZT20-23 4.95842 4.95842 4.95842