condition mean min max ZT0-3 2.28682 2.28682 2.28682 ZT4-7 1.64835 1.64835 1.64835 ZT8-11 1.1287815 1.1287815 1.1287815 ZT12-15 1.0532195 1.0532195 1.0532195 ZT16-19 1.8165200000000001 1.8165200000000001 1.8165200000000001 ZT20-23 2.275625 2.275625 2.275625