Category: asreml

  • Split-plot 1: How does a linear mixed model look like?

    I like statistics and I struggle with statistics. Often times I get frustrated when I don’t understand and I really struggled to make sense of Krushke’s Bayesian analysis of a split-plot, particularly because ‘it didn’t look like’ a split-plot to me. Additionally, I have made a few posts discussing linear mixed models using several different…

  • Bivariate linear mixed models using ASReml-R with multiple cores

    Bivariate linear mixed models using ASReml-R with multiple cores

    A while ago I wanted to run a quantitative genetic analysis where the performance of genotypes in each site was considered as a different trait. If you think about it, with 70 sites and thousands of genotypes one is trying to fit a 70×70 additive genetic covariance matrix, which requires 70*69/2 = 2,415 covariance components.…

  • Rstudio and asreml working together in a mac

    December and January were crazy months, with a lot of travel and suddenly I found myself in February working in four parallel projects involving quantitative genetics data analyses. (I’ll write about some of them very soon) Anyhow, as I have pointed out in repeated occasions, I prefer asreml-R for mixed model analyses because I run…

  • Tall big data, wide big data

    Tall big data, wide big data

    After attending two one-day workshops last week I spent most days paying attention to (well, at least listening to) presentations in this biostatistics conference. Most presenters were R users—although Genstat, Matlab and SAS fans were also present and not once I heard “I can’t deal with the current size of my data sets”. However, there…

  • Surviving a binomial mixed model

    Surviving a binomial mixed model

    A few years ago we had this really cool idea: we had to establish a trial to understand wood quality in context. Sort of following the saying “we don’t know who discovered water, but we are sure that it wasn’t a fish” (attributed to Marshall McLuhan). By now you are thinking WTF is this guy…