condition mean min max ZT0-3 2.8886258333333332 0.9219275 4.103795 ZT4-7 1.0666085 1.0666085 1.0666085 ZT8-11 1.1750254999999998 1.1750254999999998 1.1750254999999998 ZT12-15 1.76760975 0.7116695 2.82355 ZT16-19 2.2703800000000003 2.2703800000000003 2.2703800000000003 ZT20-23 4.022735 4.022735 4.022735