condition mean min max ZT0-3 8.00451 8.00451 8.00451 ZT4-7 6.98659 6.98659 6.98659 ZT8-11 7.37537 7.37537 7.37537 ZT12-15 7.358765 7.358765 7.358765 ZT16-19 7.66736 7.66736 7.66736 ZT20-23 7.62401 7.62401 7.62401