condition mean min max ZT0-3 10.564067 10.564067 10.564067 ZT4-7 13.479040999999999 13.479040999999999 13.479040999999999 ZT8-11 11.3684095 11.3684095 11.3684095 ZT12-15 9.8414665 9.8414665 9.8414665 ZT16-19 9.9777685 9.9777685 9.9777685 ZT20-23 9.909459 9.909459 9.909459