Erdogan CEVHER - 6 months ago 206

R Question

(reproducible example given) In the following, I get an abline line with y-intercept is about 30, but the regression says y-intercept should be 37.2851 Where am I wrong?

`mtcars$mpg # 21.0 21.0 22.8 ... 21.4 (32 obs)`

mtcars$wt # 2.620 2.875 2.320 ... 2.780 (32 obs)

regression1 <- lm(mtcars$mpg ~ mtcars$wt)

coef(regression1) # mpg ~ 37.2851 - 5.3445wt

plot(mtcars$mpg ~ mtcars$wt, pch=19, col='gray50') # pch: shape of points

abline(h=mean(mtcars$mpg), lwd=2, col ='darkorange') # The y-coordinate of hor'l line: 20,09062

abline(lm(mtcars$mpg ~ mtcars$wt), lwd=2, col ='sienna')

I looked at all the similar abline problems in SOF. Still, I could not figure out what is wrong in the course.

Answer