condition mean min max ZT0-3 2.650195 1.63238 4.18406 ZT4-7 20.98135 20.98135 20.98135 ZT8-11 12.22165 12.22165 12.22165 ZT12-15 1.6307415 0.991568 2.269915 ZT16-19 0.569561 0.569561 0.569561 ZT20-23 0.584711 0.584711 0.584711