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rplotvisualizationlinespoints

Regression Line to Data Points/ How to create vertical lines?

How one can get the following visualization in R (see below): let's consider a simple case of three points.

# Define two vectors
x <- c(12,21,54)
y <- c(2, 7, 11)

# OLS regression
ols <- lm(y ~ x)

# Visualisation
plot(x,y, xlim = c(0,60), ylim =c(0,15))    
abline(ols, col="red")

What I desire is, to draw the vertical distance lines from OLS line (red line) to points. enter image description here

Solution

  • If you construct a matrix of points, you can use apply to plot the lines like this:

    Create a matrix of coordinates:

    cbind(x,x,y,predict(ols))
#   x  x  y          
#1 12 12  2  3.450920
#2 21 21  7  5.153374
#3 54 54 11 11.395706

    This can be plotted as:

    apply(cbind(x,x,y,predict(ols)),1,function(coords){lines(coords[1:2],coords[3:4])})

    effectively a for loop running over the rows of the matrix and plotting one line for each row.