如何在R中绘制线性回归? [英] how to plot the linear regression in R?

问题描述

我想在R中进行以下线性回归的情况

I want to make the following case of linear regression in R

year<-rep(2008:2010,each=4)
quarter<-rep(1:4,3)
cpi<-c(162.2,164.6,166.5,166.0,166.4,167.0,168.6,169.5,170.0,172.0,173.3,174.0)
plot(cpi,xaxt="n",ylab="CPI",xlab="")
axis(1,labels=paste(year,quarter,sep="C"),at=1:12,las=3)
fit<-lm(cpi~year+quarter)

我想画一条线来显示我处理的数据的线性回归.我尝试过:

I want to plot the line that shows the linear regression of the data that I process. I have tried with:

abline(fit)
abline(fit$coefficients[[1]],c(fit$coefficients[[2]],fit$coefficients[[3]]))

问题在于我的公式的格式为:

The problem is that my formula is of the form:

y=a+b*year+c*quarter

而不是像这样简单的东西:

and not something simpler like:

y=a+b*year

那我怎么画那条显示线性回归的线呢?

so how I can draw that line that shows the linear regression?

可以用abline画线吗?

Is it possible to draw the line with abline?

推荐答案

您是否正在寻找predict函数?

例如:使用lines(predict(fit))将给出:

您还可以使用它来预测与计算出的系数一致的未来数据.例如

You could also use this for predicting future data aligning with the calculated coefficients. E.g.

# plot the existing data with space for the predicted line
plot(c(cpi,rep(NA,12)),xaxt="n",ylab="CPI",xlab="",ylim=c(162,190))

# plot the future predictions as a line using the next 3 year periods
lines(13:24,
      predict(
        fit,
        newdata=data.frame(year=rep(c(2011,2012,2013),each=4),quarter=rep(1:4,3))
             )
     )

year<-rep(2008:2013,each=4)
axis(1,labels=paste(year,quarter,sep="C"),at=1:24,las=3)

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