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By Robin High (robinh@darkwing.uoregon.edu)
While many people use statistical programs on their personal computers, they might also want to be reminded that UO computing systems have very sophisticated and powerful statistics software packages that are available free to all faculty, staff, and students.
OREGON Software. Statistics packages on OREGON include SAS, SPSS, SCA, SHAZAM, LINDO, LIMDEP, and PRELIS/LISREL. Programs can be submitted in batch mode by writing the code with a text editor such as pico.
For example, to run a SAS program, enter the program commands into a file called myfile.sas and type
$ sas myfileThe .sas extension is not necessary when submitting the command. You will always be given a file called myfile.log where you can check the execution for completeness, and if it produced output, you'll find it in a file called myfile.lis. SAS and SPSS can also be run in a more interactive mode through an X-Windows interface.
DARKWING Software. DARKWING statistics packages include sas, bmdp, Splus, eqs, and rats. (Note that DARKWING is case-sensitive, so the program names must be entered exactly as shown.) To run a program, first edit it with a text editor and then submit the command:
% sas myfile
A file called myfile.log will also be produced on DARKWING, and output will appear as myfile.lst. Each of these programs has its own command structure.
ALPHA Software. ALPHA, another UNIX-based system, should be used for computationally intensive programs written in sas, spss, and Splus. As DARKWING and ALPHA are both UNIX systems, their commands are interchangeable. All your DARKWING files are accessible on ALPHA: just log on to ALPHA with your DARKWING userid and password.
To run an spss program on ALPHA, enter
% spss -m myfile.sps > myfile.lis
Running statistical programs in batch mode requires you to write a set of computer codes in a syntax file to perform the desired tasks. One feature of some of the latest versions of personal computer programs is a "point and click" style of moving from one window or task to the next. While this method has its advantages, far too often people work their way into oblivion, not keeping a record of what they did. A step-by-step record allows you to grasp the complete picture of what was done and places you in a better position to repeat the process in future, if necessary.
Assuming you can type and are able to use a text editor, one of the real strengths of writing code in sas, spss, Splus, and other statistical programs is that these programs document the entire procedure. All the steps you take, from initial input to final data analysis, are clearly written into the program. This is known as the "syntax" method.
Although both the "point and click" and "syntax" methods are available with PC versions of the major statistical programs (e.g., SPSS 8.0 for Windows), documentation of the process is often not written into a syntax file. This makes it easy to lose track of the sequence of steps or options selected. It also takes more time to repeat the analysis later or transfer your data to another user without confusion. The syntax method is also highly efficient if you have a lot of repetitive tasks or many variables to process.