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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what is the maximum practical number of levels for ANOVA [on hold]

I'm trying to find a reference on the maximum practical number of levels in a factor for ANOVA. I know theoretically, there is no limit, but I find that after some number of levels, the results ...
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39 views

How can I run an analysis of variance with one independent variable and multiple dependent variables?

From my limited statistical knowledge, I could use MANOVA if I had multiple independent variables (x1, x2...xn). What can I do (specifically in R) with one "x" variable and multiple "y" groups? I'm ...
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30 views

How to report confidence intervals for an interaction?

I have a significant interaction in a repeated measures ANOVA. Two groups in my data are significantly different from one another. In order to report the overall confidence intervals, when I report ...
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1answer
18 views

post-hoc for non homogeneous data

Which post-hoc test is used for non homogeneous data. I have checked my data set and they are normally distributes. I used Anova with Levene's test and it showed that my data is not homogeneous, and ...
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25 views

1-way and 2-way ANOVA giving wildly different results

I'm hoping someone can help me understand this. I'm using sigmastat 10. My data consists of multiple outcomes (2 continuous and 2 count) belonging to 3 groups (test/sham/naive). If I perform a 1-way ...
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75 views

data analysis, dissertation of thesis? help please?

I'm having a problem with my dissertation. My research is "level of satisfaction in relation to customer service: comparative study between 2 fast foods my questionnaire consists of 19 questions. ...
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20 views

anova, I'm a newbie - how?

I have 2 groups, C and P. For each group I have 6 conditions. Each of these conditions has a timeseries of data i.e. 2 secs of data, 501 samples (Note,this is averaged across subjects in each group). ...
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14 views

Power/Sample size calculation with R pwr.anova.test

I would like to use pwr.anova.test (R package) to calculate power or sample sizes etc. The function needs several parameters: pwr.anova.test(k = NULL, n = NULL, f = NULL, sig.level = 0.05, power = ...
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36 views

Curse of dimensionality mimics multicollinearity?

Why does the curse of dimensionality mimic multicollinearity, in the following sense.. Consider the random vector $Y = [y_{1}, \dots, y_{4}]$ where each element is ~ Uniform (0,1). Take 10 samples ...
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1answer
13 views

Testing GLIMMIX assumptions

I am currently doing GLIMMIX models in SAS. I choosed GLIMMIX as my data is count data, generally well described by a Poisson distribution. My question: What assumptions can you test to ensure that ...
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3answers
52 views

ANOVA with outlier group

This is my first question (previously the search function has been enough), so please bear with me. I have a very simple experimental design with one outcome variable and 5 groups. My typical ...
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resort to performing a two-way instead of a one-way analysis of variance? (½ pt.). Explain two important gains by doing this [closed]

(f) Explain why we divide the mean square for treatment by the mean square for error to get the value with which the significance of the treatment effect is determined?
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Comparing non nested models [closed]

Why can we compare anova and linear regression model without nesting? one model includes continuous variable and the other model includes the categorical variable
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104 views

I just don't get the t-test

I know it sounds abysmally ignorant, but here we go. I understand the basic logic behind the t-test: you want to know whether the difference in the mean of two samples is due to chance or not. To ...
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8 views

Two Way ANOVA with Repeated Measures, Greenhouse-Geiser test shows no significant difference although pairwise comparison tables shows a difference?

I have run a statistical test on a batch of data and it has thrown me off course. I have run a two way ANOVA with repeated measures and when running through the output of data from this test firstly ...
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17 views

Two-way Repeated Measures ANOVA with replicated measures

My experiment involves 16 participants with a dependent variable (PP) tested under 2 conditions, across 3 different time-points. At every time-point, each participant is tested twice. My data is ...
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1answer
36 views

Statistical significance test: One way Anova and Kruskal-Wallis test

I was comparing data between two groups and for each group there was six samples. My data are as follows: group 1: 103.56, 103.32, 103.32, 104.27, 103.56, 103.8 group 2: 97.16, 97.16, 96.69, 98.58, ...
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1answer
21 views

does ANOVA have to work on groups with replicates? [duplicate]

I want to test if the means of different groups (tissue types) are different using one-way ANOVA. Most of the groups have replicates but there is one group that only has one sample. Like this: heart, ...
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78 views

Appropriateness of ANOVA after k-means cluster analysis

The notification after the ANOVA table after K-means analysis indicates that significance levels should not be looked at as the test of equal means, as the cluster solution has been derived based on ...
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27 views

Sample size for ANOVA

Is there minimum sample size for each group in 1-way ANOVA? if yes, please give a reference(s), If no, why there is not?
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13 views

Effect sizes for post-hoc paired comparisons in one-way ANOVA

Is there any alternative (like Cohen's d in t-test) to report about effect sizes for post-hoc paired comparisons in a one-way ANOVA (3 factor levels, correlated samples)?. Many thanks!!
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1answer
31 views

Mixed ANOVA post hoc analysis (and multiple comparisons)

I have a set of 12 subjects: 6 administred with drug A and 6 with drug B. For each subject two time-points have been collected (before and after drug treatment) for each analyte (over 6000). I had a ...
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1answer
57 views

Post-hoc tests for 2x2 ANOVAs (Type II & III) with interactions in R

I am trying to analyze data from an experiment using R and ran across a problem regarding the use of post-hoc tests with Type II & III ANOVAs. I only know of R functions that perform post-hoc ...
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3answers
41 views

Simulate data for 2 x 2 ANOVA with interaction

What is the best way to simulate ANOVA data for a 2 x 2 design with interaction using a regression approach? I want to generate the data so that I know the true regression coefficients of the model ...
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1answer
33 views

Detecting a step change in time ordered data

Suppose I have data which looks like this: ...
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$2^3$ Factorial Design conducted in a Latin Square Design

When does the situation occur to conduct a $2^3$ Factorial Design in a Latin Square Design? What would be the procedure of analyzing data of a $2^3$ Factorial Design conducted in a Latin Square ...
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56 views

Design of Experiments

Suppose a dermatologist wants to study the effectiveness of two different preparations of a skin lotion using two different forms of application, such as one versus two applications per day. She has ...
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Comparing means between 3 categories across 10 subjects with repeated-measures

I have 10 animals ("fish") with 30 trials for each one of them. Those 300 trials are classified into 3 categories ("classification") and each trial is associated with a continuous variable ...
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23 views

ANOVA on ranks?

Once in a statistics class I've seen the suggestion that one non-parametric approach for ANOVA would be to perform the ANOVA analysis on the ranks of the original data (basically as an alternative to ...
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26 views

Preparing microarray data for batch effect detection by anova

I am working on a meta-analysis of clear-cell renal cell carcinoma data. The data are gene expression values obtained out of Affymetrix Human Genome U133 Plus 2.0 arrays. Currently, I am trying to ...
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1answer
42 views

Random and Fixed effect model

Would you explain a practical situation where random effect model is more appropriate than the fixed effect model?
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Fractional Factorial Design with Highest Resolution

In the book Design and Analysis of Experiments by Douglas C. Montgomery , it is written that We usually like to employ fractional designs that have the ...
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1answer
49 views

Linear Regression In R and test of constant variance

I am trying to construct a regression model in R.I am getting an error while predicting the model. I am not sure if the newdata(which is my validation set) should be a data frame? ...
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1answer
21 views

Number of contrasts in an orthogonal contrast test

This is my first time asking a question here, so please let me know if anything is unclear. So I was trying to learn how to set up contrasts from this page, and here is the code: ...
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44 views

ANOVA for paired data

I'm asking just of curiosity. If I have, for example, paired data and 3 groups (for example, baseline, 1 week, 2 weeks of treatment: I mean we take some samples at the baseline, then we apply some ...
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Chi-Square analysis after ANOVA and correlations failed to give results

I have a continuous dependent variable and two independent grouping variables of age and gender. Age has three groups and gender two (obviously!). Now ANOVA has shown no differences across both. ...
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Can student's t and ANOVA be used to analyze a non scalar invariant interval variable?

On Cognitive Sciences I asked the question which statistical test can be used to analyze NASA TLX results. Here I will ask a similar, but more generalized question. Suppose an interval variable which ...
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Transforming data with a limited range (0,1,2) for parametric testing (ANOVA) [duplicate]

I've collected data on accuracy of recognition of images. Accuracy is a score out of 2 with points 0,1,2.. participants can score a 0. I am aiming to use a parametric test (ANOVA mixed design) to ...
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1answer
26 views

Transforming data with a limited range (0,1,2) for parametric testing (ANOVA)

I've collected data on accuracy of recognition of images. Accuracy is a score out of 2 with points 0,1,2.. participants can score a 0. I am aiming to use a parametric test (ANOVA mixed design) to ...
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1answer
41 views

Interpreting output from anova() when using lm() as input [duplicate]

I am learning about building linear regression models by looking over someone elses R code. Here is the example data I am using: ...
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35 views

Sample size in 2 x 2 x 2 mixed experimental design

I'm currently doing my university thesis, and I am unsure what sample size is required in order to achieve an acceptable statistical power. I have recruited them online, via posts on forums and ...
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22 views

Building a linear mixed effects model?

Study Design I have a dependent variable (PP), collected under two different conditions (Condition) in ten subjects (Subject) of varying heights (Height), across three different trials (Trial). Both ...
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2answers
27 views

How to compare AR and ARIMA models?

Relatively new to stats. I use linear regression and get R^2, which is quite low. MODEL 1 lmoutar=lm(formula = ts_y ~ ts_y_lag + ts_x) So switched to arima ...
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1answer
28 views

Repeated measures ANOVA with replicated measurements.

I have performed an experiment testing 3 different modes of operation on 16 participants. Each mode of operation was tested twice per user. ...
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1answer
30 views

Fractional Factorial Design

In a $2^5$ design, it is believed that only the main effects $(A,B,C,D, E)$ and $AB,AC$ interaction effects are non-zero. I need to construct a fractional factorial with minimum number of runs which ...
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26 views

$2^{5-2}$ Design : Alias Structure

$2^{5-2}$ Design Design Generators: $D=AB\quad E=AC$ Defining Relation: $I=ABD=ACE=BCDE$ $$\text{Aliases}$$ $$A=BD=CE=ABDE$$ $$B=AD=ABCE=CDE$$ $$C=ABCD=AE=BDE$$ $$D=AB=ACDE=BCE$$ ...
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38 views

Standard error bars overlap but significance - estimated marginal means versus observed means

I'm running a Mixed effects model ANOVA with two fixed factors (condition, repetition) and one random factor (subject). Subsequently, a Tukey multiple comparisons test is performed. Now I'd like to ...
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8 views

ICC to assess independence of observations in a cluster randomized trial

How can I compute an ICC to assess independence of observation assumption using SPSS for ANOVA. The data on two DVs were collected from participants one time over 28 weeks in 28 clusters (so this is ...
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post hoc test other than Tukey of factorial Anova data in R

I am looking for help on post-hoc test of my group data (treatment and stage and interaction) after 2 way anova in R software. The data shown below is a example only actually my data shows significant ...
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I am running the correct test?

I'm trying to test whether in a particular location the density of invertebrates measured now is significantly different from the one measured a decade ago. I sampled the same two plots (A and B) that ...