condition mean min max ZT0-3 13.921067 13.921067 13.921067 ZT4-7 12.753275 12.753275 12.753275 ZT8-11 11.204437 11.204437 11.204437 ZT12-15 11.829881 11.829881 11.829881 ZT16-19 14.5152305 14.5152305 14.5152305 ZT20-23 12.633500999999999 12.633500999999999 12.633500999999999