condition mean min max ZT0-3 5.904833333333333 4.422995 7.463075 ZT4-7 3.8717300000000003 3.8717300000000003 3.8717300000000003 ZT8-11 4.91183 4.91183 4.91183 ZT12-15 6.0696275 5.59577 6.543485 ZT16-19 2.97255286 2.97255286 2.97255286 ZT20-23 7.18793 7.18793 7.18793