condition mean min max ZT0-3 8.622087 8.622087 8.622087 ZT4-7 9.0896765 9.0896765 9.0896765 ZT8-11 8.2725545 8.2725545 8.2725545 ZT12-15 8.5267775 8.5267775 8.5267775 ZT16-19 8.6287565 8.6287565 8.6287565 ZT20-23 8.677659 8.677659 8.677659