condition mean min max ZT0-3 8.081577 8.081577 8.081577 ZT4-7 8.765459 8.765459 8.765459 ZT8-11 9.1290745 9.1290745 9.1290745 ZT12-15 9.2328995 9.2328995 9.2328995 ZT16-19 8.157645500000001 8.157645500000001 8.157645500000001 ZT20-23 9.3144365 9.3144365 9.3144365