condition mean min max ZT0-3 6.805557500000001 6.1223600000000005 7.488755 ZT4-7 6.56121 6.56121 6.56121 ZT8-11 3.77288 3.77288 3.77288 ZT12-15 0 0 0 ZT16-19 7.05109 7.05109 7.05109 ZT20-23 6.794185000000001 6.794185000000001 6.794185000000001