condition mean min max ZT0-3 0.353727 0.353727 0.353727 ZT4-7 0.2506155 0.2506155 0.2506155 ZT8-11 0.3138425 0.3138425 0.3138425 ZT12-15 0.28334349999999997 0.28334349999999997 0.28334349999999997 ZT16-19 0.333168 0.333168 0.333168 ZT20-23 0.216832 0.216832 0.216832