condition mean min max ZT0-3 1.4777433333333334 1.224235 1.8371300000000002 ZT4-7 1.1039715 1.1039715 1.1039715 ZT8-11 2.0720650000000003 2.0720650000000003 2.0720650000000003 ZT12-15 5.8600675 5.837405 5.8827300000000005 ZT16-19 4.63293 4.63293 4.63293 ZT20-23 3.10511 3.10511 3.10511