condition mean min max ZT0-3 8.48381 8.48381 8.48381 ZT4-7 8.2879005 8.2879005 8.2879005 ZT8-11 8.6743695 8.6743695 8.6743695 ZT12-15 9.086648499999999 9.086648499999999 9.086648499999999 ZT16-19 9.4733645 9.4733645 9.4733645 ZT20-23 8.745068499999999 8.745068499999999 8.745068499999999