在R中的两个数据集中的一张图上绘制两个简单的线性回归散点图和直线

Question

I have tried:

plot(CORTMaglog~CORTlogB, data = data0, xlab="logCORTB", ylab="log CORT30- CORTB")
abline(lm(CORTMaglog ~ CORTlogB))

and

plot(CORTMaglog~CORTlogB, data = data1, xlab="logCORTB", ylab="log CORT30- CORTB")
abline(lm(CORTMaglog ~ CORTlogB))

and now have two graphs.

How do I have both plots from two different data sets on one graph with lines and scatterplots?

Thank you!

Answer 1

You should use points . Here is a reproducible example:

x = 1:100
y1 = x^1.2 + x*rnorm(100,0,1)
y2 = 2*x^1.2 + x*rnorm(100,1,0.5)
plot(x,y1)
plot(x,y2)

data1 = cbind(x,y1)
data2 = cbind(x,y2)

plot(y2 ~ x, data=data2,col='blue')
abline(lm(y2 ~ x),col='blue')

points(y1 ~ x, data=data1,col='red')
abline(lm(y1 ~ x),col='red')

Edit To answer the question in the comments. To use the plot function the way you want to, you need to extract the predictions from the predict function. For example:

x = 1:100
y1 = x^1.2 + x*rnorm(100,0,1)
data1 = data.frame(cbind(x,y1))

fit = lm(y1~x, data=data1)
y = predict(fit, newdata = data.frame(x))
plot(x,y1)
lines(x,y)