condition mean min max ZT0-3 31.2 31.2 31.2 ZT4-7 6.1 6.1 6.1 ZT8-11 42.099999999999994 42.099999999999994 42.099999999999994 ZT12-15 25.700000000000003 25.700000000000003 25.700000000000003 ZT16-19 7.0 7.0 7.0 ZT20-23 11.85 11.85 11.85