Message-ID: <65079.5717.qm@web120612.mail.ne1.yahoo.com>
Date: 2010-12-01T09:00:16Z
From: Iasonas Lamprianou
Subject: missing values
Dear all,
i have spent a lot of time trying to solve this problem, but I am sure that
there must be a simple solution. So, as a last resort, I am coming back to you
again. I have a dataset with some (almost random) values in many variables. Lets
say that the dataset represents the scores of students to test questions. What I
need to do is to sum the scores for each student. However, wherever there is a
missing (NA) value, I cannot get the total score. How can I compute the total
score and the average per question (a) by ignoring the missing responses, (b) by
assuming that a missing response is a zero?
Thank you for the response
Dr. Iasonas Lamprianou
Assistant Professor (Educational Research and Evaluation)
Department of Education Sciences
European University-Cyprus
P.O. Box 22006
1516 Nicosia
Cyprus
Tel.: +357-22-713178
Fax: +357-22-590539
Honorary Research Fellow
Department of Education
The University of Manchester
Oxford Road, Manchester M13 9PL, UK
Tel. 0044 161 275 3485
iasonas.lamprianou at manchester.ac.uk