Hi, (a) sum() and mean() have a na.rm argument that should be set to TRUE.
(b) let's try with an example: x <- c(1:5, NA, NA, 6:10, NA) x[is.na(x)] <- 0 ## replace NAs by 0 HTH, Ivan Le 12/1/2010 10:00, Iasonas Lamprianou a écrit :
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.lampria...@manchester.ac.uk ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
-- Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. Säugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 ivan.calan...@uni-hamburg.de ********** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
