condition mean min max ZT0-3 8.992961 8.992961 8.992961 ZT4-7 8.8759385 8.8759385 8.8759385 ZT8-11 9.785635 9.785635 9.785635 ZT12-15 9.826243999999999 9.826243999999999 9.826243999999999 ZT16-19 8.7769615 8.7769615 8.7769615 ZT20-23 9.9110905 9.9110905 9.9110905