A new version of Racket (8.16) has just been released. There’s now full support for Student t distribution. Easy upgrade (pending a minor issue with Homebrew installed libzmq):
brew upgrade
raco pkg migrate 8.15
rm -rf ~/Library/Racket/8.15
cp /opt/homebrew/Cellar/zeromq/4.3.5_1/lib/libzmq.5.dylib ~/Library/Racket/8.16/lib
raco iracket install