condition mean min max ZT0-3 2.3268950000000004 2.15092 2.50287 ZT4-7 3.163575 3.163575 3.163575 ZT8-11 1.865905 1.865905 1.865905 ZT12-15 0 0 0 ZT16-19 1.43008 1.43008 1.43008 ZT20-23 2.39457 2.39457 2.39457