condition mean min max ZT0-3 4.041259999999999 4.041259999999999 4.041259999999999 ZT4-7 3.904235 3.904235 3.904235 ZT8-11 3.446345 3.446345 3.446345 ZT12-15 5.158815000000001 5.158815000000001 5.158815000000001 ZT16-19 8.546453333333334 8.546453333333334 8.546453333333334 ZT20-23 7.55403 7.55403 7.55403