condition mean min max ZT0-3 15.199825 15.1187 15.28095 ZT4-7 15.22785 15.22785 15.22785 ZT8-11 14.74165 14.74165 14.74165 ZT12-15 0 0 0 ZT16-19 18.98515 18.98515 18.98515 ZT20-23 17.32515 17.32515 17.32515