LISP-STAT is an Enviroment for Statistical Computing and Dynamic Graphics developed by Luke Tierney. XLISP-Stat is a specific implementation based on XLISP, a public domain variant of Common LISP.
Several authors have created software based on Lisp-Stat, namely
On this site we will mostly use ARC for analysis, i.e. an XLISPSTAT environment to which ARC has been added, i.e. you can use both ARC and XLISP-STAT.