condition mean min max ZT0-3 3.047851666666667 2.648885 3.47708 ZT4-7 1.8669799999999999 1.8669799999999999 1.8669799999999999 ZT8-11 2.71064 2.71064 2.71064 ZT12-15 6.1006875 5.15987 7.041505000000001 ZT16-19 4.479025 4.479025 4.479025 ZT20-23 5.1614 5.1614 5.1614