condition mean min max ZT0-3 7.785907 7.785907 7.785907 ZT4-7 8.7723625 8.7723625 8.7723625 ZT8-11 7.7819635 7.7819635 7.7819635 ZT12-15 8.1553445 8.1553445 8.1553445 ZT16-19 7.3700995 7.3700995 7.3700995 ZT20-23 7.4636455 7.4636455 7.4636455