condition mean min max ZT0-3 14.5903 14.5903 14.5903 ZT4-7 8.638605 8.638605 8.638605 ZT8-11 8.263125 8.263125 8.263125 ZT12-15 7.0675 7.0675 7.0675 ZT16-19 12.40305 12.40305 12.40305 ZT20-23 17.0471 17.0471 17.0471