Raw data can be manipulated in the datastep. This is often done prior to the analysis of the data using SAS procedures. Here's an example.
In a math course, the course grade is based on the scores on 3 midterms and a final exam. The midterms are worth 20% each; the final worth 40%. On each test 100 points are possible. Here's an example of a datastep which inputs data and computes the course total.
data score;
input last $ first $ m1-m3 final;
total=0.2*m1+0.2*m2+0.2*m3+0.4*final;
cards;
brown susan 75 82 35 88
smith james 22 92 45 97
run;
proc print data=score;
run;
Copy this program into the program editor window, select LOCAL--SUBIMT from the menu there, and see how it runs.
The data set score will contain a variable total which is the
weighted average of the midterm and final exam scores. Note the use
of the subscripted variable m to stand for the 3
midterm scores.
The usual trigonometric, exponential, logarithmic, and arithmetic functions are available for use in the data step. The functions topic gives a partial listing of other specialized functions which are available.
This concludes the tutorial. You may wish to begin working on a project to get experience in data step programming and the use of SAS procedures in the analysis of data.
Copyright © 1997 by Jerry Alan Veeh. All rights reserved.