condition mean min max ZT0-3 9.707831 9.707831 9.707831 ZT4-7 10.660728 10.660728 10.660728 ZT8-11 9.931058 9.931058 9.931058 ZT12-15 9.322714 9.322714 9.322714 ZT16-19 10.040333 10.040333 10.040333 ZT20-23 11.691857500000001 11.691857500000001 11.691857500000001