condition mean min max ZT0-3 6.93173 6.93173 6.93173 ZT4-7 5.72614 5.72614 5.72614 ZT8-11 5.5656300000000005 5.5656300000000005 5.5656300000000005 ZT12-15 6.9033 6.9033 6.9033 ZT16-19 10.925934999999999 10.925934999999999 10.925934999999999 ZT20-23 7.41408 7.41408 7.41408