condition mean min max ZT0-3 4.864240000000001 4.864240000000001 4.864240000000001 ZT4-7 3.1107750000000003 3.1107750000000003 3.1107750000000003 ZT8-11 3.47988 3.47988 3.47988 ZT12-15 4.42446 4.42446 4.42446 ZT16-19 6.28201 6.28201 6.28201 ZT20-23 6.527 6.527 6.527