ANOVA stands for ANalysis Of VAriance, a statistical model and set of procedures for comparing multiple group means. The independent variables in an ANOVA model are categorical, but an ANOVA table can be used to test continuous variables as well.

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Is a Mixed type III anova appropriate for unequal N data? How does one run this analysis in R?

I have a dataset from a psychological experiment that consists of three repeated measures of responses to different kinds of items 'variable', as well as two between-subject IVs, 'condition' and ...
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Understanding ANOVA for comparison of models in R. Why is the result the same regardless of model order?

I'm trying to figure out why the anova function in R gives me the same results (for the p-value) regardless of the order of the models. ...
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Is there something called “mean coding” (like dummy coding & effect coding) in regression models?

When we perform a regression analysis with categorical predictors, we can use (1, 0), called "dummy coding". The coefficients in this case represent the deviation of the groups' means from the mean of ...
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Tukey Multiple Comparision

I used GLM to run a Tukey multiple comparison. The p-value of model was 0.6483; so the model is not significant. The differences of pairs show there is not a significant difference of means ...
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25 views

Why do we ignore the main effects when the interactions are not significant in a three-way ANOVA?

I'm following an SPSS guide online, and the procedure is to first test for a three-way interaction. In my case there was no sig. three-way interaction. Then the procedure asks me to consider two-way ...
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Multiple DVs - MANOVA or multiple ANOVAs?

My project has multiple continuous DVs and a single categorical IV. When I run ANOVA for each of my DVs the means and SDs are different to when I use MANOVA. Why is that? Which one is correct? Which ...
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27 views

Testing for differences between populations of individuals with binomial data

So I am trying to compare between populuations and determine whether there is a difference in count based data. My data look like this: ...
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1answer
14 views

GAM summary F values

Does anyone know how the F values are computed in summary(gam.object). I've looked through the help page, and the gam package, ...
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Test Control. A longitudinal study

I have two samples of the same size, one being the 'treated' group, and the other used as a 'control' group. Each group have a different univariate variable (stress level), repeatedly observed over ...
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54 views

How to analyze data once broken down into gender, race, etc

I have two conditions, Treatment A, and Treatment B. Participants are randomly assigned to a treatment at the outset. Then I run unpaired t-tests on the data to find any differences. BUT I am also ...
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Permutation to test SNP interactions

sampleID case/ctrl var1 var2 var3 var4 var5... sample1 0 1 0 0 1 0 1... sample2 1 0 0 0 0 1 0... sample3 0 1 1 1 0 0 0... sample4 1 0 0 0 0 1 0... ... case/ctrl status is binary, variant status is ...
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Best way to test that one mean is greater than all the others

Suppose I have $k$ samples of different sizes, each of a different univariate variable. I want to test the significance of the hypothesis that the population of $k_0$ has a mean greater than all of ...
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Planned comparisons and experiment-wise error rate in factorial experiments

When using planned comparisons in the context of factorial experiments is it still necessary to compensate for the inflation of the experiment-wise error rate? My planned comparisons involve 4 ...
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19 views

3way between subjects Anova with Unbalanced samples

I would like to perform robust 3-way ANOVA using the WRS package in R. The very first requirement is to cast the data into wide format. Hence, I have wide format data frame with unbalanced rows in ...
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17 views

Degree of freedom in post-hoc test

I have a crucial question (crucial for a statistic beginner as me...) I have run a 2x2 repeated meausure ANOVA between subjects where I had: Factor Between: Subject Category (14 musicians/14 ...
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Mixed ANOVA interaction effect - How do I which treatment was more effective?

I have conducted a mixed between-within ANOVA with 3 intervention groups and 2 measurement times (pre/post) in SPSS. There was a significant Time*Group interaction, but significant main effects. How ...
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44 views

Two sample tests for stratified randomization

I have to test the difference between two samples which were selected via stratified randomization. The problem is that the samples are not independent due to randomization was stratified. How should ...
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21 views

Heteroskedasticity of error term in log-level models?

I am running a decomposition of log wages for two time periods and want to explain the variance of the error term. My question is: If there is a wage growth trend, will this automatically increase ...
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1answer
86 views

What tool should I use to find improper relationship between doctor and patient?

I have a data table in R where I summarized the dollar value of prescribed medicines for each doctor-patient combination. In all, I have about half a million observations, with about 3000 doctors and ...
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46 views

Centering variables in R [closed]

Do centered variables have to stay in matrix form when using them in a regression equation? I have centered a few variables using the scale function with ...
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ANOVA statistic question [closed]

I need some help with a problem. Here is my question: Looking at the results of the ANOVA (see data below), is there a significant difference in the mean alcohol content for beers in the three quality ...
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Which test do I need to apply for repeated measures?

My research question is as follows: How does on-ground presence of bird species A, B, and C change in relation to: 1. species A breeding chronology, and 2. time of day/month My data consists of ...
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1answer
52 views

Repeated Measures ANOVA and the Bonferroni post hoc test different results of significantly

I am doing an Repeated Measures ANOVA and the Bonferroni post hoc test for my data using R project. The ANOVA gives a significantly difference between the data but not the Bonferroni post hoc test. ...
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ANOVA for multiple repeated measurements

My dataset consist of the following columns: ...
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26 views

Should I use repeated meaure ANOVA?

I have 5 interaction techniques (eg., interaction 1 to 5) and I have recruited 15 participants to participate in my study. Each participant interacts with each of these 5 techniques only once. I will ...
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Is ANOVA the same as running 3 t-tests?

I have a group of subjects which did tests under 3 different conditions. If I now want to compare variables with a ANOVA, is it right that I get the same p-values as if I would run 3 t-tests ...
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How to interpret the direction of a covariate's effect in a 2-way ANOVA?

I use SPSS's GLM (general linear model) to analyze an data set based on a 2x2 between-subjects experimental design. The design has two factors: a). congruence (yes or no) and d). primed image ...
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How to interpret the output of the anova command in R? [duplicate]

I used the anova function in R to get an ANOVA table for my model. ...
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29 views

GLM or arcsine and two-way ANOVA

I am trying to analyse data on how long deer have been vigilant in a 2 minute observational period and how this varies between males and females and also whether they were in the centre or edge of the ...
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What will be the best test to determine the significance in this study?

The project does not have a simple design. It is planned as follows: It is a longitudinal observation during 120 days in 48 subjects (with repeated measures using multiple tests); The subjects were ...
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Nested ANOVA for species, genera, etc in R

I am wondering how to set up a nested ANOVA in R that will show me whether the greatest variance in genome size is found at the order, family, etc. level. My data would be in columns with the ...
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Who first stated the relationship between ANOVA and linear regression?

ANOVA is usually thought as equivalent to linear regression, which is very interesting. Who first discovered this fact? Did Fisher know about this when he worked on ANOVA?
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Do two-way ANOVA data need to be strictly balanced?

I conducted an experiment of 2x2 between-subjects design. So there is four conditions with the two factors. However, after deleting the data that failed to pass manipulation check, the four conditions ...
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2answers
26 views

Overall significance of multiple downward trends?

I am uncertain how to formally establish that I observe a negative relationship between X and Y in multiple sets of linked data points. I have analyzed several cells in which values of interest (Y) ...
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Anova types R: which to use

I would like to perform an ANOVA analysis to determine which factors can explain most of the variance for a response variable y ~ A + B + A:B + C My data are ...
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1answer
48 views

Should I use ANOVA or MANOVA?

I would like to compare the performance of two algorithms A and B under various conditions. Performance is measured on a ratio scale. In a simplified setting, the input data set is a factor (DS1, DS2, ...
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26 views

ANOVA representation

This question can seem quite stupid. I know that there are two ways of representing ANOVA model. For example, in one-way ANOVA the model can be written as: $$ y_{ij} = \mu + a_j + e_{ij} $$ where $i$ ...
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How to correct for multiple post-hoc tests in multi-factor ANOVA

Let's for the sake of this question assume we did an ANOVA with three factors A (3 levels), B (4 levels), and C (5 levels). We get significant main effects for A and B. In consequence we do three ...
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1answer
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post hoc test for 3 way anova

I am doing ANOVA using three fixed independent factors of which one is sex (two levels 'male' and 'female'), temperature (three levels: 1,2,3) and quality (two levels: good and bad) and I want to see ...
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How to determine how much of the variation in a binary dependent variable can be determined from a set of independent variables?

I'm working with a dataset of legislative voting results in the brazilian Chamber of Deputies. I have a list of votes (mapped as 1 and 0 for Yes and No), like: ...
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Help with repeated measures analysis in a complex design

I'm looking at a study measuring blood flow in the brain, there are 8 subjects in this study, with 18 measurements each. The measurements are done 6 at a time in three different time points ...
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Anova Error term complexity unnecessary?

There is often confusion about properly using Error term in anova. However, following example show that the output remains the same whether it is a simple entry of Error(subject) or more complex ones. ...
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Mixed-design ANOVA or one-way ANOVA with delta values

I have an experiment with one independent variable with 4 levels (4 different treatments) and 1 dependent variable which was measured twice - before and after the treatment (repeated measures). I ...
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1answer
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testing contrast in two-way ANOVA using multcomp

I am trying to compare two levels of a factor aggregated over the levels of another one using the multcomp package. I use a "between-subjects-version" of the dataset obk.long contained in the afex ...
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So survey data cannot be normal distributed?

I am analyzing a data from survey. The data is from a 2X2 between subjects experiment design with 45 subjects in each of the four conditionsThe questions are based on a 5-point or 10-point scale. ...
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3answers
141 views

Should I adjust p-values when investigating an ANOVA interaction?

I'm conducting an experiment to compare 4 types of headphones. I'm interested in finding out whether the headphones differ in their subjective quality. Thirty subjects listened to each pair of ...
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32 views

post hoc test for unequal sample size and variance

I have a data frame on which I am doing ANOVA using three fixed independent factors of which one is gender (two levels 'male' and 'female'), temperature (three levels: 1,2,3) and quality (two levels: ...
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14 views

Anova with interaction only between some factors

I would like to perform an ANOVA analysis to determine which factors can explain most of the variance for the response variable y ~ A + B + A:B + C + B:C where ...
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16 views

Can I perform multiple ANOVAs over many time intervals, instead of one 2-way ANOVA?

Full question : Can I perform multiple ANOVAs over many time intervals if I am only interested in comparing means between the groups in each time interval (ie not interested in a 2-way ANOVA?)Do I ...
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Intra-class correlation and ANOVA for multi-class classification?

I have trained and evaluated with leave-one-out cross-validation classifiers (SVM, logistic regression, deep belief network, gaussian naive bayes, k-nearest neighbour) on my dataset. My dataset ...