condition mean min max ZT0-3 20.716727 20.716727 20.716727 ZT4-7 21.4612105 21.4612105 21.4612105 ZT8-11 22.189664 22.189664 22.189664 ZT12-15 22.790718 22.790718 22.790718 ZT16-19 22.694252499999997 22.694252499999997 22.694252499999997 ZT20-23 20.279559499999998 20.279559499999998 20.279559499999998