condition mean min max ZT0-3 7.934001 7.934001 7.934001 ZT4-7 7.5356495 7.5356495 7.5356495 ZT8-11 7.896326 7.896326 7.896326 ZT12-15 8.2481 8.2481 8.2481 ZT16-19 7.173562499999999 7.173562499999999 7.173562499999999 ZT20-23 7.4599325 7.4599325 7.4599325