pm10=[352,179,383,463,670,451,426,302,566]
 pm25=[251,93,189,262,427,284,264,177,346]
 plot(pm10,pm25,'+');//绘出散点图
 lsline;//根据散点图绘出直线
 a=corrcoef(pm10,pm25);//获取相关系数矩阵
 s=['pm10','pm25']
 text(pm10,pm25,s);//在线上加标注
 title('pm10、pm25相关性分析');
 legend('pm10','pm25');
 xlabel('PM10(ug/m3)');
 ylabel('PM2.5(ug/m3)');
 grid;//添加网格
 axis square;//坐标轴成正方形