condition mean min max ZT0-3 12.685265 12.685265 12.685265 ZT4-7 17.26868 17.26868 17.26868 ZT8-11 17.4556945 17.4556945 17.4556945 ZT12-15 19.6131155 19.6131155 19.6131155 ZT16-19 13.872469500000001 13.872469500000001 13.872469500000001 ZT20-23 13.446873 13.446873 13.446873