condition mean min max ZT0-3 27.448589 27.448589 27.448589 ZT4-7 17.580209 17.580209 17.580209 ZT8-11 18.8337055 18.8337055 18.8337055 ZT12-15 15.7638225 15.7638225 15.7638225 ZT16-19 19.7562605 19.7562605 19.7562605 ZT20-23 21.536920000000002 21.536920000000002 21.536920000000002