[R] Not the same length

[varin sacha]

Dear R-helpers,

Doing dput(x) and dput(y_obs), the 2 vectors are not the same length (1800 for y_obs and 2000 for x)
How can I solve the problem ? 

Here is the reproducible R code 

  #  #  #  #  #  #  #  #  #  #
library(mgcv) 
 library(earth) 

n<-2000 
x<-runif(n, 0, 5)   
 y_model<- 0.1*x^3 - 0.5 * x^2 - x + 10   
y_obs<-rnorm(n*0.9, y_model, 0.1)+rnorm(n*0.1, y_model, 0.5) 
gam_model<- gam(y_obs~s(x)) 
mars_model<- earth(y_obs~x)   
MSE_GAM<-mean((gam_model$fitted.values - y_model)^2) 
MSE_MARS<-mean((mars_model$fitted.values - y_model)^2)   
MSE_GAM 
MSE_MARS
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