condition mean min max ZT0-3 6.218116666666667 5.797095 6.8824000000000005 ZT4-7 5.01299 5.01299 5.01299 ZT8-11 5.49588 5.49588 5.49588 ZT12-15 7.376844999999999 7.183615 7.570074999999999 ZT16-19 5.854889999999999 5.854889999999999 5.854889999999999 ZT20-23 8.679145 8.679145 8.679145