condition mean min max ZT0-3 7.612964 7.612964 7.612964 ZT4-7 8.3677295 8.3677295 8.3677295 ZT8-11 7.5130155 7.5130155 7.5130155 ZT12-15 11.727832 11.727832 11.727832 ZT16-19 7.835471 7.835471 7.835471 ZT20-23 8.080962 8.080962 8.080962