condition mean min max ZT0-3 13.892225 13.892225 13.892225 ZT4-7 11.160630999999999 11.160630999999999 11.160630999999999 ZT8-11 11.6723525 11.6723525 11.6723525 ZT12-15 12.974537999999999 12.974537999999999 12.974537999999999 ZT16-19 15.551423 15.551423 15.551423 ZT20-23 10.096642 10.096642 10.096642