276 search results for "Anova"

How do I re-arrange??: Ordering a plot revisited

August 14, 2013
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How do I re-arrange??: Ordering a plot revisited

Back in October of last year I wrote a blog post about reordering/rearanging plots. This was, and continues to be, a frequent question on list serves and R help sites. In light of my recent studies/presenting on The Mechanics of … Continue reading →

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More rainfall calculations – REML

August 4, 2013
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More rainfall calculations – REML

I wanted to have a look at various REML methods for a long time. The rainfall data seemed a nice example. On top of that, FreshBiostats had a blog post 'Mixed Models in R: lme4, nlme, or both?'. So lme4 it is.The data  As described before; th...

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Uncertainty in parameter estimates using multilevel models

August 3, 2013
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David Hsu writes: I have a (perhaps) simple question about uncertainty in parameter estimates using multilevel models — what is an appropriate threshold for measure parameter uncertainty in a multilevel model? The reason why I ask is that I set out to do a crossed two-way model with two varying intercepts, similar to your flight The post Uncertainty...

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Advanced sab-R-metrics: Parallelization with the ‘mgcv’ Package

July 18, 2013
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Advanced sab-R-metrics: Parallelization with the ‘mgcv’ Package

Carson Sievert (creator of the really neat pitchRx package) and Steamer Projections posed a question about reasonable run times of the mgcv package on large data in R yesterday, and promised my Pitch F/X friends I would post here with a quick tip on sp...

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Evaluating the Potential Incorporation of R into Research Methods Education in Psychology

July 17, 2013
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I was recently completing some professional development activities that required me to write a report on a self-chosen topic related to diversity in student backgrounds. I chose to use the opportunity to reflect on the potential for using R to teach psychology students research methods. I thought I'd share the report in case it interests anyone. Abstract...

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Some Common Approaches for Analyzing Likert Scales and Other Categorical Data

July 1, 2013
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Some Common Approaches for Analyzing Likert Scales and Other Categorical Data

Analyzing Likert scale responses really comes down to what you want to accomplish (e.g. Are you trying to provide a formal report with probabilities or are you trying to simply understand the data better). Sometimes a couple of graphs are sufficient and a formalize statistical test isn’t even necessary. However, with how easy it is

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Hey, I Just did a Significance Test!

June 7, 2013
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Hey, I Just did a Significance Test!

I’ve seen it happens quite often. The sig test. Somebody simply needs to know the p-value and that one number will provide all of the information about the study that they need to know. The dataset is presented and the client/boss/colleague/etc invariably asks the question “is it significant?” and “what’s the correlation?”. To quote R.A.

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(Another) introduction to R

May 27, 2013
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(Another) introduction to R

It’s Memorial Day and my dissertation defense is tomorrow. This week I’m phoning in my blog. I had the opportunity to teach a short course last week that was part of a larger workshop focused on ecosystem restoration. A fellow grad student and I taught a session on Excel and R for basic data analysis.

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Omni test for statistical significance

May 9, 2013
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Omni test for statistical significance

In survey research, our datasets nearly always comprise variables with mixed measurement levels – in particular, nominal, ordinal and continuous, or in R-speak, unordered factors, ordered factors and numeric variables. Sometimes it is useful to be able to do blanket tests of one set of variables (possibly of mixed level) against another without having to

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Mixed Model Example — Wagner et al. (2006)

May 6, 2013
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Mixed Model Example — Wagner et al. (2006)

I am preparing for a workshop on mixed models and looked at the paper “Accounting for multilevel data structures in fisheries data using mixed models” by Wagner et al. (2006) (PDF available here).  Wagner et al. (2006) used two examples, with the … Continue reading →

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