Assignment Two, Quiz on Friday Sept. 26th

Bring a printout of your list file to the quiz. Bring a calculator. Don't write on the printout, except for your name and student number. If anything besides your name and student number is written on your printout, you will be charged with academic dishonesty and turned over to Dean Krull.

The Scholastic Aptitude Test (SAT) is a test used by American universities to screen students for admission. There are two sub-tests, the Verbal and the Mathematical. Total SAT score is the sum of these two. In my public directory is a file called grades.dat. Get a copy for yourself with

cp /student/jbrunner/public/grades.dat .

The period is important. It refers to your current directory.

Grades.dat has Verbal SAT, Math SAT and first-year GPA (in that order) for a sample of university students. First, LOOK AT THE DATA. Just page through it with less and look at it. You should always do this.

Make an SPSS command file to read the data, calculate total SAT score for each student, and label all the variables. Calculate the mean and standard deviation of each variable, and do a correlation matrix of all the variables. Note that all variables means including total score, but not including case number.

Think about these questions for the quiz. Which variables are significantly related? What proportion of the variation in GPA is explained by total SAT score? What proportion of the variation in GPA is explained by verbal SAT score? Is there anything funny about doing so many significance tests on one set of data? Explain. If you were really interested in these data and not just doing what you are told, what additional things would you do with SPSS, and why?

In addition, quiz two will present several short descriptions of hypothetical studies. You will be asked to name the independent variable or variables, name the dependent variable, name the most appropriate significance test, and say whether the study is experimental or observational.