condition mean min max ZT0-3 2.6224083333333335 2.15874 3.4323300000000003 ZT4-7 1.80681 1.80681 1.80681 ZT8-11 2.1368799999999997 2.1368799999999997 2.1368799999999997 ZT12-15 2.5215825 2.38693 2.656235 ZT16-19 3.12702 3.12702 3.12702 ZT20-23 3.6079 3.6079 3.6079