condition mean min max ZT0-3 4.04705 4.04705 4.04705 ZT4-7 2.93042 2.93042 2.93042 ZT8-11 2.547865 2.547865 2.547865 ZT12-15 2.833525 2.833525 2.833525 ZT16-19 3.58232 3.58232 3.58232 ZT20-23 3.554395 3.554395 3.554395