condition mean min max ZT0-3 14.962216666666668 12.5713 16.5176 ZT4-7 11.17075 11.17075 11.17075 ZT8-11 7.712540000000001 7.712540000000001 7.712540000000001 ZT12-15 6.2333715000000005 4.585973 7.88077 ZT16-19 12.26135 12.26135 12.26135 ZT20-23 16.26075 16.26075 16.26075