condition mean min max ZT0-3 1.99459596 1.99459596 1.99459596 ZT4-7 2.5226550000000003 2.5226550000000003 2.5226550000000003 ZT8-11 4.18432 4.18432 4.18432 ZT12-15 2.8888249999999998 2.8888249999999998 2.8888249999999998 ZT16-19 3.423923333333333 3.423923333333333 3.423923333333333 ZT20-23 6.25368 6.25368 6.25368