Purnima Chawla (pchawla@ETS.ORG) wrote:
: Hello, everyone.
: I'm trying to do a cluster analysis based on how people have responded to
: a survey. Some of the questions in the survey required a Y/N response
: and thus yield binomial data. Others required a Likert type response;
: still others were designed like multiple choice questions but are graded
: and can be interpreted as ordinal data.
: My question is this: how should the proximities be calculated if some of
: the data are binomial and some are ordinal? Also, does SPSS do this?
a) SPSS Proximities has a number of possibilities for scoring
distances or proximities for binomial data. It is possible to use
a subset of variables, and create a Distance-score from dichotomies;
then use that as just one among another set of variables.
b) the default (without STANDARDIZE) means that a variable scored
0-100 would have 10 or 100 times the weight as a variable scored 1-10.
c) the choice of VARIABLES going into your distances is what the
weighting will be computed over; if there are 10 trivial variables
and one important one, the distances will be not depend much on the
Rich Ulrich, biostatistician email@example.com
http://www.pitt.edu/~wpilib/index.html Univ. of Pittsburgh