condition mean min max ZT0-3 7.898759 7.898759 7.898759 ZT4-7 8.9949715 8.9949715 8.9949715 ZT8-11 9.0228885 9.0228885 9.0228885 ZT12-15 7.8342695 7.8342695 7.8342695 ZT16-19 8.7003465 8.7003465 8.7003465 ZT20-23 8.5065515 8.5065515 8.5065515