condition mean min max ZT0-3 11.947468 11.947468 11.947468 ZT4-7 12.760911 12.760911 12.760911 ZT8-11 13.1239595 13.1239595 13.1239595 ZT12-15 12.2703965 12.2703965 12.2703965 ZT16-19 12.484072999999999 12.484072999999999 12.484072999999999 ZT20-23 14.3114735 14.3114735 14.3114735