190 search results for "ANova"

Serious stats: using multilevel models to get accurate inferences for repeated measures ANOVA

June 13, 2013
By

This article from my other blog may be of interest to readers of this blog: http://seriousstats.wordpress.com/2013/04/18/using-multilevel-models-to-get-accurate-inferences-for-repeated-measures-anova-designs/

Read more »

Hey, I Just did a Significance Test!

June 7, 2013
By
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.

Read more »

(Another) introduction to R

May 27, 2013
By
(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.

Read more »

Omni test for statistical significance

May 9, 2013
By
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

Read more »

Simulation shows gain of clmm over ANOVA is small

May 5, 2013
By
Simulation shows gain of clmm over ANOVA is small

After last post's setting up for a simulation, it is now time to look how the models compare. To my disappointment with my simple simulations of assessors behavior the gain is minimal. Unfortunately, the simulation took much more time than I ...

Read more »

Ordinal data, models with observers

April 21, 2013
By

I recently made three posts regarding analysis of ordinal data. A post looking at all methods I could find in R, a post with an additional method and a post using JAGS. Common in all three was using the cheese data, a data set where...

Read more »

Using multilevel models to get accurate inferences for repeated measures ANOVA designs

April 18, 2013
By
Using multilevel models to get accurate inferences for repeated measures ANOVA designs

It is now increasingly common for experimental psychologists (among others) to use multilevel models (also known as linear mixed models) to analyze data that used to be shoe-horned into a repeated measures ANOVA design. Chapter 18 of Serious Stats introduces multilevel models by considering them as an extension of repeated measures ANOVA models that can

Read more »

R 3.0.0 is released! (what’s new, and how to upgrade)

April 3, 2013
By
R 3.0.0 is released! (what’s new, and how to upgrade)

A few hours ago Peter Dalgaard (of R Core Team) announced the release of R 3.0.0!  Bellow you can read the changes in this release. One of the features worth noticing is the introduction of long vectors to R 3.0.0. As David Smith …

Read more »

Read more »

Veterinary Epidemiologic Research: GLM – Logistic Regression (part 2)

March 17, 2013
By
Veterinary Epidemiologic Research: GLM – Logistic Regression (part 2)

Second part on logistic regression (first one here). We used in the previous post a likelihood ratio test to compare a full and null model. The same can be done to compare a full and nested model to test the contribution of any subset of parameters: Interpretation of coefficients Note: Dohoo do not report the

Read more »

Ordinal Data

March 17, 2013
By
Ordinal Data

I expect to be getting some ordinal data, from 5 or 9 point rating scales, pretty soon, so I am having a look ahead how to treat those. Often ANOVA is used, even though it is well known not to be ideal fro a statistical point of view, so that is the st...

Read more »