condition mean min max ZT0-3 8.38195091 7.363802528 9.400099292 ZT4-7 11.350452034 9.825839198 12.87506487 ZT8-11 15.4354308275 13.30752882 17.563332834999997 ZT12-15 16.143610975 15.53446722 16.75275473 ZT16-19 13.72947335375 11.587821117499999 15.871125590000002 ZT20-23 7.112912682 5.2220954934999995 9.0037298705