[R] installing caret package

[Elahe chalabi]

Hi all,

I'm using Rstudio 64 bit version3.2.5 and I faced a problem installing caret package,the error is :

Loading required package: lattice
Loading required package: ggplot2
Error : object ‘sigma’ is not exported by 'namespace:stats'
Error: package or namespace load failed for ‘caret’

how should I solve the problem with this sigma?!

Thanks for any help.
Elahe