SAS is statistical software created by SAS Institute, Inc which is used by large organizations, including many public agencies, to do data management and analysis. SAS is preferred (and most often used) when working with very large datasets because it does not require a powerful computer to do so. Although and perhaps because it is very powerful, the syntax is difficult to learn. Social Scientists who do not intend to work at one of the public agencies and do not work with extremely large data sets might consider learning R or Stata instead.
SAS Studio is a tool that you can use to write and run SAS code through your web browser. With SAS Studio, you can access your data files, libraries, and existing programs and write new programs. When you use SAS Studio, you are also using SAS software behind the scenes. SAS Studio connects to a SAS server in order to process SAS commands.
NYU's Quantitative Analysis Guide - Look-up table to choose a statistical test
Links directly to relevant pages in the following useful resources