condition mean min max ZT0-3 12.915662 12.915662 12.915662 ZT4-7 13.0758355 13.0758355 13.0758355 ZT8-11 13.686816499999999 13.686816499999999 13.686816499999999 ZT12-15 12.9018805 12.9018805 12.9018805 ZT16-19 13.340332499999999 13.340332499999999 13.340332499999999 ZT20-23 13.404042 13.404042 13.404042