condition mean min max ZT0-3 7.3418025 6.972635 7.71097 ZT4-7 6.149825 6.149825 6.149825 ZT8-11 4.778085 4.778085 4.778085 ZT12-15 0 0 0 ZT16-19 7.8233 7.8233 7.8233 ZT20-23 7.37637 7.37637 7.37637