condition mean min max ZT0-3 2.719885 2.719885 2.719885 ZT4-7 2.04195 2.04195 2.04195 ZT8-11 1.71714 1.71714 1.71714 ZT12-15 3.66104 3.66104 3.66104 ZT16-19 7.80007 7.80007 7.80007 ZT20-23 4.119945 4.119945 4.119945