Why am I getting same linear regression lines for 'x' on 'y' and 'y' on 'x'?

Question

[glyptonotus]

Hi all,

I am plotting data instances attending to two different variables (x, y) and the linear regression line between them: lm(x~y). I don't understand why, when I plot the opposite relationship: lm(y~x), I get a very similar line, instead of a specular/opposed one. Showing figure 1 (x~y), I would expect a line like the green one in figure 2 (y~x), but I get the red line.

I have checked the linear regression code in both cases:

lm(formula=x~y, data=data) # for figure 1
lm(formula=y~x, data=data) # for figure 2

Could anyone suggest any possible mistake I am doing? Thank you.

[Ram]

This post does not fit the theme of this forum. Please consult stats SE.

[karl.stamm]

Check the dataset, it looks quite symmetrical, maybe erroneously it really is the same in x and y.