condition mean min max ZT0-3 2.35855 2.35855 2.35855 ZT4-7 1.407925 1.407925 1.407925 ZT8-11 1.862885 1.862885 1.862885 ZT12-15 3.525405 3.525405 3.525405 ZT16-19 4.266605 4.266605 4.266605 ZT20-23 3.159365 3.159365 3.159365