condition mean min max ZT0-3 168.845779 168.845779 168.845779 ZT4-7 184.5178505 184.5178505 184.5178505 ZT8-11 134.627792 134.627792 134.627792 ZT12-15 159.0695705 159.0695705 159.0695705 ZT16-19 142.5524785 142.5524785 142.5524785 ZT20-23 202.663938 202.663938 202.663938