condition mean min max ZT0-3 3.0894250000000003 3.0894250000000003 3.0894250000000003 ZT4-7 2.675465 2.675465 2.675465 ZT8-11 2.2916600000000003 2.2916600000000003 2.2916600000000003 ZT12-15 2.9305 2.9305 2.9305 ZT16-19 3.6343449999999997 3.6343449999999997 3.6343449999999997 ZT20-23 2.770445 2.770445 2.770445