condition mean min max ZT0-3 1.1484443333333332 0.9302115 1.2661354999999999 ZT4-7 0.4769035 0.4769035 0.4769035 ZT8-11 0.4368975 0.4368975 0.4368975 ZT12-15 0.88935925 0.845411 0.9333075 ZT16-19 0.6783605 0.6783605 0.6783605 ZT20-23 1.165291 1.165291 1.165291