condition mean min max ZT0-3 9.007788333333334 4.25348 13.984100000000002 ZT4-7 2.881155 2.881155 2.881155 ZT8-11 4.1246599999999995 4.1246599999999995 4.1246599999999995 ZT12-15 9.183017499999998 9.15705 9.208984999999998 ZT16-19 9.265025 9.265025 9.265025 ZT20-23 16.98295 16.98295 16.98295