condition mean min max ZT0-3 4.457985 4.457985 4.457985 ZT4-7 3.29997 3.29997 3.29997 ZT8-11 4.607215 4.607215 4.607215 ZT12-15 5.165675 5.165675 5.165675 ZT16-19 8.11424 8.11424 8.11424 ZT20-23 4.821375 4.821375 4.821375