condition mean min max ZT0-3 4.341378333333333 2.3956049999999998 5.5524249999999995 ZT4-7 1.418005 1.418005 1.418005 ZT8-11 2.123285 2.123285 2.123285 ZT12-15 2.75014 2.240015 3.260265 ZT16-19 4.940615 4.940615 4.940615 ZT20-23 6.131349999999999 6.131349999999999 6.131349999999999