condition mean min max ZT0-3 6.6600375000000005 6.40197 6.918105000000001 ZT4-7 4.021255 4.021255 4.021255 ZT8-11 5.0132650000000005 5.0132650000000005 5.0132650000000005 ZT12-15 0 0 0 ZT16-19 7.084664999999999 7.084664999999999 7.084664999999999 ZT20-23 7.311585000000001 7.311585000000001 7.311585000000001