condition mean min max ZT0-3 3.89873 2.619805 4.72473 ZT4-7 2.1401649999999997 2.1401649999999997 2.1401649999999997 ZT8-11 3.06937 3.06937 3.06937 ZT12-15 3.8457850000000002 3.20872 4.48285 ZT16-19 4.9081 4.9081 4.9081 ZT20-23 6.8571550000000006 6.8571550000000006 6.8571550000000006