condition mean min max ZT0-3 6.802875 6.802875 6.802875 ZT4-7 5.88737 5.88737 5.88737 ZT8-11 6.15774 6.15774 6.15774 ZT12-15 3.99581 3.99581 3.99581 ZT16-19 5.16498 5.16498 5.16498 ZT20-23 3.917205 3.917205 3.917205