Factor Analysis in short (not my writing)

What is Factor Analysis?*
"Factor analysis is a form of exploratory multivariate analysis that is used to either reduce the number of variables in a model or to detect relationships among variables. All variables involved in the factor analysis need to be interval and are assumed to be normally distributed."

SPSS syntax:

factor
/variables read write math science socst
/criteria factors(2)
/extraction pc
/rotation varimax
/plot eigen.

Here is the syntax in SPSS from ANU course notes:

FACTOR
/VARIABLES q34_1 to q34_12
/MISSING LISTWISE /ANALYSIS q34_1 to q34_12
/PRINT INITIAL KMO REPR EXTRACTION ROTATION
/CRITERIA MINEIGEN(1) ITERATE(25)
/FORMAT SORT
/EXTRACTION PAF
/CRITERIA ITERATE(25)
/ROTATION VARIMAX
/METHOD=CORRELATION .

Crate SCALE using FA

FACTOR
/VARIABLES q34_1 to q34_12
/MISSING LISTWISE /ANALYSIS q34_1 to q34_12
/PRINT INITIAL KMO REPR EXTRACTION ROTATION
/CRITERIA MINEIGEN(1) ITERATE(25)
/FORMAT SORT
/EXTRACTION PAF
/PLOT EIGEN
/CRITERIA ITERATE(25)
/ROTATION VARIMAX
/SAVE REG (2)
/METHOD=CORRELATION .



*Introduction to SAS. UCLA: Academic Technology Services, Statistical Consulting Group. from http://www.ats.ucla.edu/stat/sas/notes2/ (accessed November 24, 2007).