Hi Timesaver, thanks for your advise. The reason that 'randomForest' is not available for R3.5.1 is not the typo.
The first message I receive after executing code is:
1 package is needed for this model and is not installed. (randomForrest). Would you like to try to install it now?
1: yes
2: no
After a attempt to install I get
Warning in install.packages :
package ‘randomforrest’ is not available (for R version 3.5.1)
The package randomForest 4.6-14 is installed in R3.5.1.
I'm confused
Antoin