condition mean min max ZT0-3 21.558445 21.558445 21.558445 ZT4-7 19.291897 19.291897 19.291897 ZT8-11 22.1535805 22.1535805 22.1535805 ZT12-15 21.195103000000003 21.195103000000003 21.195103000000003 ZT16-19 24.728174 24.728174 24.728174 ZT20-23 23.028781000000002 23.028781000000002 23.028781000000002