condition mean min max ZT0-3 9.667875 9.667875 9.667875 ZT4-7 8.6615055 8.6615055 8.6615055 ZT8-11 8.637189 8.637189 8.637189 ZT12-15 8.862643 8.862643 8.862643 ZT16-19 8.4586785 8.4586785 8.4586785 ZT20-23 7.833786 7.833786 7.833786