condition mean min max ZT0-3 13.023325 11.58095 14.4657 ZT4-7 7.9307549999999996 7.9307549999999996 7.9307549999999996 ZT8-11 8.005379999999999 8.005379999999999 8.005379999999999 ZT12-15 0 0 0 ZT16-19 12.6697 12.6697 12.6697 ZT20-23 12.5546 12.5546 12.5546