condition mean min max ZT0-3 8.223894 8.223894 8.223894 ZT4-7 8.643854000000001 8.643854000000001 8.643854000000001 ZT8-11 8.036903 8.036903 8.036903 ZT12-15 9.1219115 9.1219115 9.1219115 ZT16-19 8.198612 8.198612 8.198612 ZT20-23 8.1451675 8.1451675 8.1451675