condition mean min max ZT0-3 2.417075 2.417075 2.417075 ZT4-7 0.731894 0.731894 0.731894 ZT8-11 1.822185 1.822185 1.822185 ZT12-15 0.9365815 0.9365815 0.9365815 ZT16-19 2.163055 2.163055 2.163055 ZT20-23 2.497955 2.497955 2.497955