condition mean min max ZT0-3 24.013125 22.49055 25.5357 ZT4-7 15.8064 15.8064 15.8064 ZT8-11 16.1087 16.1087 16.1087 ZT12-15 0 0 0 ZT16-19 21.504350000000002 21.504350000000002 21.504350000000002 ZT20-23 19.60235 19.60235 19.60235