condition mean min max ZT0-3 21.29868 21.29868 21.29868 ZT4-7 19.5156955 19.5156955 19.5156955 ZT8-11 18.852003 18.852003 18.852003 ZT12-15 16.999096 16.999096 16.999096 ZT16-19 13.950168999999999 13.950168999999999 13.950168999999999 ZT20-23 14.9169615 14.9169615 14.9169615