condition mean min max ZT0-3 37.618376 37.618376 37.618376 ZT4-7 35.069488 35.069488 35.069488 ZT8-11 33.66509 33.66509 33.66509 ZT12-15 31.639861 31.639861 31.639861 ZT16-19 42.629464999999996 42.629464999999996 42.629464999999996 ZT20-23 54.044382999999996 54.044382999999996 54.044382999999996