condition mean min max ZT0-3 1.2445898333333334 1.1224995 1.358725 ZT4-7 1.604915 1.604915 1.604915 ZT8-11 2.4159100000000002 2.4159100000000002 2.4159100000000002 ZT12-15 2.034405 1.98041 2.0884 ZT16-19 2.1231549999999997 2.1231549999999997 2.1231549999999997 ZT20-23 1.902095 1.902095 1.902095