condition mean min max ZT0-3 267.985485 267.985485 267.985485 ZT4-7 188.1598065 188.1598065 188.1598065 ZT8-11 166.9543135 166.9543135 166.9543135 ZT12-15 173.6160165 173.6160165 173.6160165 ZT16-19 252.90740399999999 252.90740399999999 252.90740399999999 ZT20-23 264.85022100000003 264.85022100000003 264.85022100000003