condition mean min max ZT0-3 17.22775 15.09665 19.35885 ZT4-7 19.01555 19.01555 19.01555 ZT8-11 15.026150000000001 15.026150000000001 15.026150000000001 ZT12-15 0 0 0 ZT16-19 16.64045 16.64045 16.64045 ZT20-23 24.03725 24.03725 24.03725