condition mean min max ZT0-3 243.259828 243.259828 243.259828 ZT4-7 263.4606815 263.4606815 263.4606815 ZT8-11 300.184345 300.184345 300.184345 ZT12-15 266.4883965 266.4883965 266.4883965 ZT16-19 153.3333265 153.3333265 153.3333265 ZT20-23 140.455921 140.455921 140.455921