273 search results for "ANOVA"

Two-way analysis of variance: two-way ANOVA in R

August 7, 2009
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The one-way analysis of variance is a useful technique to verify if the means of more groups are equals. But this analysis may not be very useful for more complex problems. For example, it may be necessary to take into account two factors of variability to determine if the averages between the groups depend on the group classification...

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Analysis of variance: ANOVA, for multiple comparisons

July 30, 2009
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Analysis of variance: ANOVA, for multiple comparisonsThe ANOVA model can be used to compare the mean of several groups with each other, using a parametric method (assuming that the groups follow a Gaussian distribution).Proceed with the following example:The manager of a supermarket chain wants to see if the consumption in kilowatts of 4 stores between them are equal. He...

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Analysis of variance: ANOVA, for multiple comparisons

July 30, 2009
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Analysis of variance: ANOVA, for multiple comparisonsThe ANOVA model can be used to compare the mean of several groups with each other, using a parametric method (assuming that the groups follow a Gaussian distribution).Proceed with the following example:The manager of a supermarket chain wants to see if the consumption in kilowatts of 4 stores between them are equal. He...

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Repeated Measures ANOVA using R

March 9, 2009
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Repeated Measures ANOVA using R

While so-called “between-subjects” ANOVA is absolutely straightforward in R, performing repeated measures (within-subjects) ANOVA is not so obvious. I have come across at least three different ways of performing repeated measures ANOVA in R. Which method you use depends on … Continue reading →

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Analysis of Variance (ANOVA) using R

February 5, 2009
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Analysis of Variance (ANOVA) using R

I found some useful websites showing examples of how to use R for various sorts of ANOVA (between, within, mixed designs, etc): Using R for Psychological Research Quick-R for SAS/SPSS/Stata users enjoy

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An adverse consequence of fitting "maximal" linear mixed models

August 23, 2014
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An adverse consequence of fitting "maximal" linear mixed models

Distribution of intercept-slope correlation estimates with 37 subjects, 15 itemsDistribution of intercept-slope correlation estimates with 50 subjects, 30 itemsShould one always fit a full variance covariance matrix (a "maximal" model) when one analyze...

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What your twitter friends say about you and your interests

August 10, 2014
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What your twitter friends say about you and your interests

This post is first in a series that looks at the inferences you can make using social media data. The …Continue reading →

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Guns are Cool – Differences between states

August 3, 2014
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Guns are Cool – Differences between states

Last week my blog showed that there are differences between states in the shootingtracker database. This week it is attempted to understand why states are different. A number of variables were extracted from a few sources, among which gun laws, % ...

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Comrades Marathon: A Race for Geriatrics?

July 22, 2014
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Comrades Marathon: A Race for Geriatrics?

It has been suggested that the average Comrades Marathon runner is gradually getting older. As an “average runner” myself, I will not deny that I am personally getting older. But, what I really mean is that the average age of all runners taking part in this great event is gradually increasing. This is not just

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Guns are cool – time effects

July 19, 2014
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Guns are cool – time effects

September last year I made a post using the shootingtracker data. It is attempted in shootingtracker to register all shootings with at least four victims, be they wounded or dead. The data starts  January 1st 2013, which means that by now the...

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