condition mean min max ZT0-3 2.302235 2.302235 2.302235 ZT4-7 0.5163365 0.5163365 0.5163365 ZT8-11 0.37871699999999997 0.37871699999999997 0.37871699999999997 ZT12-15 0.409266 0.409266 0.409266 ZT16-19 1.7529249999999998 1.7529249999999998 1.7529249999999998 ZT20-23 2.731725 2.731725 2.731725