condition mean min max ZT0-3 376.072218 376.072218 376.072218 ZT4-7 226.5792825 226.5792825 226.5792825 ZT8-11 207.320157 207.320157 207.320157 ZT12-15 272.141665 272.141665 272.141665 ZT16-19 414.2081115 414.2081115 414.2081115 ZT20-23 452.6390835 452.6390835 452.6390835