condition mean min max ZT0-3 31.294116666666667 30.1831 33.3746 ZT4-7 19.7334 19.7334 19.7334 ZT8-11 7.746270000000001 7.746270000000001 7.746270000000001 ZT12-15 8.204845 6.76321 9.64648 ZT16-19 9.362950000000001 9.362950000000001 9.362950000000001 ZT20-23 17.7196 17.7196 17.7196