condition mean min max ZT0-3 12.669476105 12.58500701 12.753945199999999 ZT4-7 5.1989964115 3.9962247155 6.4017681075 ZT8-11 7.665591216499999 3.2136141845 12.1175682485 ZT12-15 18.01112136 16.992593045 19.029649675 ZT16-19 13.344383377499998 12.955559919999999 13.733206834999999 ZT20-23 18.1190878075 16.938834255 19.29934136