Group-level variances and correlations

September 23, 2008

(This article was first published on Yu-Sung Su's Blog, and kindly contributed to R-bloggers)

This is just a sum-up of what we should do when we try to estimate the group-level variances and correlations but the software failed to do so. As a R and lmer() user, I found this happens often.If this is the case, there are three potential problems:(1) sd is 0(2) some correlations are -1 or 1(3) covariance matrix is singularIf the problem is of (1), then we might as well forget about the

To leave a comment for the author, please follow the link and comment on their blog: Yu-Sung Su's Blog. offers daily e-mail updates about R news and tutorials on topics such as: Data science, Big Data, R jobs, visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...

If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Tags: , ,

Comments are closed.

Search R-bloggers


Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)