condition mean min max ZT0-3 0.5872851666666667 0.0 1.2339705 ZT4-7 1.73711 1.73711 1.73711 ZT8-11 0.7138815000000001 0.7138815000000001 0.7138815000000001 ZT12-15 1.141066 0.9185345 1.3635975 ZT16-19 1.2736595 1.2736595 1.2736595 ZT20-23 0.73357 0.73357 0.73357