condition mean min max ZT0-3 9.944382 9.944382 9.944382 ZT4-7 9.232009999999999 9.232009999999999 9.232009999999999 ZT8-11 8.8871105 8.8871105 8.8871105 ZT12-15 8.361165 8.361165 8.361165 ZT16-19 9.0326655 9.0326655 9.0326655 ZT20-23 8.654939500000001 8.654939500000001 8.654939500000001