283 search results for "anova"

Bayesian modeling using WinBUGS

November 6, 2011
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Bayesian modeling using WinBUGS

Yes, yet another Bayesian textbook: Ioannis Ntzoufras’ Bayesian modeling using WinBUGS was published in 2009 and it got an honourable mention at the 2009 PROSE Award. (Nice acronym for a book award! All the mathematics books awarded that year were actually statistics books.) Bayesian modeling using WinBUGS is rather similar to the more recent Bayesian

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Migrating from SPSS/Excel to R, Part 3: Preparing your Data

October 29, 2011
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Migrating from SPSS/Excel to R, Part 3: Preparing your Data

In this post, I describe how to prepare your data for migrating between SPSS/Excel and R. This is the third …Continue reading »

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Longitudinal analysis: autocorrelation makes a difference

October 25, 2011
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Longitudinal analysis: autocorrelation makes a difference

Back to posting after a long weekend and more than enough rugby coverage to last a few years. Anyway, back to linear models, where we usually assume normality, independence and homogeneous variances. In most statistics courses we live in a … Continue reading →

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Teaching with R: the switch

October 21, 2011
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There are several blog posts, websites (and even books) explaining the transition from using another statistical system (e.g. SAS, SPSS, Stata, etc) to relying on R. Most of that material treats the topic from the point of view of i- … Continue reading →

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Linear mixed models in R

October 16, 2011
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A substantial part of my job has little to do with statistics; nevertheless, a large proportion of the statistical side of things relates to applications of linear mixed models. The bulk of my use of mixed models relates to the … Continue reading →

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Assumptions of the Linear Model

October 6, 2011
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Assumptions of the Linear Model

Linear Assumptions from the Analysis Factor – Assumptions of linear regression (and ANOVA) are about the residuals, not the normality or independence of the response variable (Y). If you don’t know what this means be sure to read this brief … Continue reading →

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Linear regression with correlated data

October 5, 2011
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I started following the debate on differential minimum wage for youth (15-19 year old) and adults in New Zealand. Eric Crampton has written a nice series of blog posts, making the data from Statistics New Zealand available. I will use … Continue reading →

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Assessing the Forecasting Ability of Our Model

September 2, 2011
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Assessing the Forecasting Ability of Our Model

Today we wish to see how our model would have faired forecasting the past 20 values of GDP. Why? Well ask yourself this: How can you know where your going, if you don't know where you've been? Once you understand please proceed on with the following post.First recall the trend portion that we have already accounted for:> t=(1:258)> t2=t^2> trendy= 892.656210 +...

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Major changes to the forecast package

August 25, 2011
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Major changes to the forecast package

The forecast package for R has undergone a major upgrade, and I’ve given it version number 3 as a result. Some of these changes were suggestions from the forecasting workshop I ran in Switzerland a couple of months ago, and some have been on the drawing board for a long time. Here are the main

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Z-Tests: Should we even bother?

August 23, 2011
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Z-Tests: Should we even bother?

Should statistical teachers continue to teach z-tests?vote:  save z-test, or stop z-testLooking at textbooks, articles and general research I cannot remember the last time I saw someone use a z-test in a study. I have seen many a t-test, ANOVA, ch...

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