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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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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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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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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51 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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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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22 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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32 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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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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18 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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35 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
21 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
32 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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34 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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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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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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24 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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30 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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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 ...
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Why is the Bonferroni correction properly used with planned, and not post hoc, contrasts?

The Wikipedia article on Post hoc analysis says "Bonferroni correction (This is properly used with planned, not post hoc, contrasts.)" but does not explain why the Bonferroni correction is properly ...
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51 views

The biological significance of ANOVA 3-way interaction

Dear statistics experts, I have trouble to find a sensible statistical approach to back up some very obvious (at least to my eyes) interpretation of a dataset (see descriptive plot below). I measure ...
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25 views

The a priori power of test for a simple effect within a 2x2 ANOVA

I need to know about the power of a simple effect that follows from a 2x2 ANOVA interaction. Let's call the factors in this design GROUP(Patient, Control) and MANIPULATION(Expectation, Random), ...
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In ANOVA, if the null hypothesis is true is the expected value of F guaranteed to be 1?

By null hypothesis is true I mean that the means of each group is the same at population level. I am wondering whether the expected value would depart from 1 in the case that the variances of the ...
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14 views

R script for split plot augmented randomized complete block experiment design

I’m working on a data set in order to evaluate the impact of water stress on Rils population. The experimental design is split plot augmented design and it's as follows: The first factor ...
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6 views

Bootstrapping with random effects in SPSS

I'd like to use bootstrapping in my two-way ANOVA containing two fixed and one random factor. Why is the bootstrapping method not available (greyed out) for models containing a random factor? Thanks! ...
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Pre-post analysis with multiple post measures

I am having trouble deciding what type of analysis to use for the following data: I have two groups (one control, one treatment) and took a pre-measure of my dependent variable, and then 3 ...
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31 views

What type of analysis

I have two data sets to compare. Each is a list of billed amounts by diagnosis codes. The data differs in that the diagnosis codes may be different for some of the billed amounts. There are ...
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22 views

Aligned Rank Transform for mixed effects ANOVA in SPSS

In a book, I've found SPSS syntax for performing an aligned rank transformation in a two way ANOVA. The procedure is: - save residuals by performing a standard ANOVA - use Aggregate to determine ...
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39 views

How to calculate p value from ANOVA function for LMM results?

I have used ANOVA function so that I can get the overall p value of significant factors: ...
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ANOVA in R: How MSresiduals are estimated when using Error(interaction)?

I have checked the existing answers, but I found no answer to my question. It is about choosing the right ANOVA model in R and how the MSresiduals are estimated. I have an experiment with two ...
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29 views

SPSS Contrasts for a Five-Way Within-Subjects ANOVA (Yes, You read correctly)

I have a 4 x 4 x 2 x 2 x 2 repeated measures design and I'm trying to test a contrast for just the first variable (here called "SOA"), averaging over the others, in SPSS. Initially, I thought it ...
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1answer
34 views

Reproducing simple t-test result with ANOVA

We know that a t-test is just a special case of ANOVA, so I tried to reproduce the result of the following t-test with aov() or ...
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38 views

Regressing, analysing data with points rather than polynomial?

I am looking into making a regression of a bunch of data that is contained on some range of real numbers. In my case, x is between 0 and 1 and y is between 0 and 10. If I have 150 data points on this ...
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31 views

Orthogonal contrasts for four levels - are Helmert contrasts orthogonal?

I am planning to do a 2-way mixed ANOVA with the within-subjects factor having four levels. Since the exact data do not matter, I hope to suffice by only providing a general question. On my ...
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Which post-hoc comparison to use and why

Hopefully this is now a much clearer picture of the question I want to answer: For each of 60 different plans I ran 35 simulation replications of my Agent Based Model (ABM) simulation. Then for each ...
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propagating errors through an ANOVA?

I'm sorry if this question has been answered before. I have a dataset: -1.5 -1.8 -1.625 -1.25 -1.525 -1.675 -1.15 -1.35 -1.65 etc Each column is ...
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Homogeneity of variance for time variable

I have four groups of plant treated with different temperatures and I conducted repeated measurement on their growth rate. I use ANOVA with Mixed Model to analyze the data by specifying both ...
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Appropriate analysis for this experimental design - non-normal data

I've run an experiment with 8 subjects, which had to perform [a series of 4] navigational tasks under 4 different vision conditions each. The experiment was repeated weekly, 16 times with the same ...
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2answers
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Directional research hypotheses vs. directional hypothesis testing

When I took a methods course, I was told to avoid making a directional hypothesis. I understand the reason. Now however, I often see hypotheses like these: "We hypothesized that reaction time will ...
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1answer
40 views

ANOVA and Count/Percent Data

I'm just starting to work with some count data and I'm still trying to understand some of the complexities of it, so any help would be greatly appreciated. First the simple version, and then the ...
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Factorial design for interactions with ordinal DV

I want to make a 4 question, multiple choice survey in which each question asks about an analogous range of actions for slightly different scenarios. Each participant would only be administered the ...