no problem./....you know this is the forum for Mac Pro's (the tower Mac) and not the portable one, right?? Ah, I'm wasting my breath talking about that...who listens to me anyways....here you can find the "R" project, which also requires XQuartz to be installed... beforehand...
https://cran.r-project.org/bin/macosx/
usually these things have to be signed, as SIP (system integrity protection is on by default.) no sign, no install
the version there is 3.3.2 and it's in PKG format, so it should be okay...
and here's how to install packages
https://cran.r-project.org/bin/macosx/RMacOSX-FAQ.html#How-to-install-packages
you might also want to see if there's an update for SPSS as well....
here's a link to the supported versions... I think they're leaning towards SPSS 24, but not sure on that...anyways read on
https://www-304.ibm.com/support/docview.wss?uid=swg21507587
I think someone has helps you as best as he can
Good luck
John B