condition mean min max ZT0-3 9.837285 9.837285 9.837285 ZT4-7 8.08404 8.08404 8.08404 ZT8-11 7.72242 7.72242 7.72242 ZT12-15 7.8375699999999995 7.8375699999999995 7.8375699999999995 ZT16-19 9.90542 9.90542 9.90542 ZT20-23 9.42473 9.42473 9.42473