condition mean min max ZT0-3 20.007 14.21995 23.31065 ZT4-7 12.54945 12.54945 12.54945 ZT8-11 11.5962 11.5962 11.5962 ZT12-15 13.22655 13.15595 13.297149999999998 ZT16-19 12.961400000000001 12.961400000000001 12.961400000000001 ZT20-23 19.219499999999996 19.219499999999996 19.219499999999996