Blog Archives

Graphing – margins, titles, mtext, workspace

February 21, 2011
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Graphing – margins, titles, mtext, workspace

This is a great post, very true, not enough of R’s graphics are well displayed online to really see how to achieve what the often ambiguous ‘help’ information suggests. http://research.stowers-institute.org/efg/R/Graphics/Basics/mar-oma/index.htm I particularly find “mtext(“lol”, outer=T)” to be particularly useful (requires “oma=c(2,2,2,2)” or similar). http://addictedtor.free.fr/graphiques/ This site is somewhat of the way there, but I’ve found

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Child health metrics

February 20, 2011
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Child health metrics

In analysis of Child Health data, generally z-scores or percentile groupings are used as children do not growth is not linear. The CDC (Center for Disease Control and Prevention) have released tables of data for calculating these z-scores and percentiles, and here are some scripts for R to calculate these in your sample. CLICK HERE

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Mixed models – Part 2: lme lmer

February 15, 2011
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Mixed models – Part 2: lme lmer

Getting more into mixed models, I’ve been playing around with both nlme::lme and lme4::lmer. http://tolstoy.newcastle.edu.au/R/e2/help/06/10/3345.html was quite a good post at explaining the differences, which from what I gather is largely performance based when using crossed or partially crossed models. In the models I am tinkering with at the moment I am noticing differences in

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Mixed Models – Part 1

February 3, 2011
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Mixed Models – Part 1

Very brief. Have been exploring mixed models in R using nlme::lme. Am looking forward to understanding them more, they’re going to be used more and more in years to come I’ve no doubt of that. Here are some scripts, very rough, for diagnostics when running simple 2 levels, or models with 1 grouping variable. CLICK

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