condition mean min max ZT0-3 7.1910300000000005 7.1910300000000005 7.1910300000000005 ZT4-7 7.867290000000001 7.867290000000001 7.867290000000001 ZT8-11 6.3953299999999995 6.3953299999999995 6.3953299999999995 ZT12-15 6.794535 6.794535 6.794535 ZT16-19 8.21187 8.21187 8.21187 ZT20-23 8.66415 8.66415 8.66415