condition mean min max ZT0-3 6.539653333333333 4.510755 7.9377949999999995 ZT4-7 4.43483 4.43483 4.43483 ZT8-11 3.85051 3.85051 3.85051 ZT12-15 6.159145 6.10319 6.2151 ZT16-19 7.007765 7.007765 7.007765 ZT20-23 9.700714999999999 9.700714999999999 9.700714999999999