condition mean min max ZT0-3 10.553713 10.553713 10.553713 ZT4-7 11.3354275 11.3354275 11.3354275 ZT8-11 12.111057500000001 12.111057500000001 12.111057500000001 ZT12-15 10.798006 10.798006 10.798006 ZT16-19 10.680554 10.680554 10.680554 ZT20-23 11.5621245 11.5621245 11.5621245