condition mean min max ZT0-3 18.50395 18.50395 18.50395 ZT4-7 18.0920185 18.0920185 18.0920185 ZT8-11 15.788866500000001 15.788866500000001 15.788866500000001 ZT12-15 14.5301205 14.5301205 14.5301205 ZT16-19 13.3506535 13.3506535 13.3506535 ZT20-23 13.797388999999999 13.797388999999999 13.797388999999999