condition mean min max ZT0-3 4.202765 4.202765 4.202765 ZT4-7 3.0417 3.0417 3.0417 ZT8-11 4.233895 4.233895 4.233895 ZT12-15 5.07882 5.07882 5.07882 ZT16-19 6.368905 6.368905 6.368905 ZT20-23 5.083535 5.083535 5.083535