condition mean min max ZT0-3 3.2339866666666666 1.5934599999999999 4.296395 ZT4-7 1.8833 1.8833 1.8833 ZT8-11 2.0487849999999996 2.0487849999999996 2.0487849999999996 ZT12-15 4.690835 4.545285 4.836385 ZT16-19 4.72804 4.72804 4.72804 ZT20-23 5.03874 5.03874 5.03874