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Questions tagged [anova]

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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Simple effects in mixed design with R

My experiment consists of two factors, one between and one within subject. Time is the between-subjects factor and hold two levels: (low and high). Times is the within-subject factors and hold three ...
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1answer
12 views

Difficulty working out which statistical test to perform

I am writing a research paper looking at how reported PTSD scores vary in those who have lost a loved one to homicide. I am investigating whether there is a difference in the scores at different ...
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30 views

How to conclude that all group means are different?

Suppose I have groups $G_1$ to $G_n$ with sample means of the variable of interest $m_1$ to $m_n$ respectively and sample variances $s_1^2$ to $s_n^2$. What tests can I perform to conclude that the ...
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1answer
11 views

Treatment Vs control analysis with two groups

I have cancer and WT controls samples from two different groups for size comparison. I would like to do some statistics to calculate p-value and perhaps get some plots. I am not very familiar with ...
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13 views

round robin table, is one player significantly better?

For my master thesis I am holding a round robin tournament for multi-agent learning algorithms (game theory), so far so good. The rewards of the players are storen in a table and now I would like to ...
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1answer
10 views

Can I use one-way ANOVA instead of repeated measures ANOVA even when data has been collected for all subjects under all the conditions?

I have data collected for 20 subjects under two conditions for each of the subject. When I want to compare the means of the two conditions, is it absolutely necessary that I use the paired T-test? My ...
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4 views

Testing if the strength a correlation is moderated by a continuous variable

Participants rated different behaviors on how risky they think the behavior is, and then rated how likely they are to engage in the behavior. I want to know if their ratings of the behavior's ...
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12 views

Specifying ANOVA with incomplete block design (R)

I have experimental data of individual sizes (continuous) as a function of two categorical variables (A and B) each with 2 levels (1 and 2), along with a control treatment. Each treatment condition ...
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9 views

Analysis for 1 observation per group [on hold]

I have a data set that counts the number of times an event occurs at several sites. This count was repeated for 5 years every time a strong storm passed. Each site is unique and each time the count ...
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1answer
25 views

A question about ANOVA

Question: My problem: Regarding the above question, a solution set was provided(although it was not explained by anyone). There the problem was solved by "One way ANOVA" model, Yij=u+eij, where ...
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7 views

How is correlation among repeated measures calculated for ANOVA interaction effect?

I am performing a replication study, of an interaction effect found in repeated measures ANOVA. The study is of a 2X2 design (1 group of subjects, 4 measurements each). To estimate the required ...
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16 views

Planned contrasts in mixed models

My experiment consists of two factors, one between and one within subject. Time is the between-subjects factor and hold two levels: (low and high). Times is the within-subject factors and hold three ...
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0answers
4 views

Which Post-Hoc Test Should Be Used in Repeated Measures (ANOVA) in SPSS

I have three experimental and one control group in my study. I have two observations for them (pre and post test). I want compare four group in those 2 observations. I choose to do "Repeated Measures-...
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1answer
27 views

Constructing 3-way ANOVA when design is not fully factorial

I have conducted an experiment measuring individual sizes as a function of two categorical variables (A and B), each with three levels (1, 2, 3). The combination A3:B3 is a control group. This ...
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12 views

The F Distribution Help - Did I answer the blanks correctly? [on hold]

The F Distribution Help - Did I answer the blanks correctly?
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1answer
33 views

weird assumption of one-way random effects ANOVA

$$Y_{ij} = μ \, +\, A_i \, +\,ε_{ij}$$ In Ch5 (random effects one-way ANOVA) of my textbook, it mentioned that $A_i$ (see the model above) is assumed to be $\sim N( 0, \text{constant_variance} )$ ...
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1answer
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How to conduct power analysis for unbalanced one-way ANOVA in R?

I am looking for a way to conduct power analysis for unbalanced one-way ANOVA in R. I found the pwd package; however, it only allows me to calculate power for ...
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6 views

Nested models and ANOVA: F ratios

I have some commuting data involving a factor B (district) that is nested inside another factor A (city). I am assuming both factors are fixed. I have calculated F ratios involving $MS_A/MS_R$ and $...
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1answer
29 views

multiple one sample t.test with ANOVA

If I want to see if the mean of 3 different groups is above a specific threshold instead of doing 3 on-sample ttest can I use anova? So instead of 3 ...
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10 views

Three Factor Multiple Comparison Post-Hoc Test for Levene's Test

My research question is to find out whether or not my samples are exhibiting any significant differences in their variance in response to three possible treatments. Here are my possible groups: ...
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13 views

Repeated measures ANOVA question

I'm new to statistics and looking for some guidance on choosing my variables for a repeated measures ANOVA. My data set consists of 4 dependent variables: 1. Gait speed 2. Balance test 3. Leg ...
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1answer
35 views

Which statistical test to use? Not really paired, not entirely unpaired

I am setting up an experiment where I would like to determine whether there exists a difference between the participants' average self reported mental effort in some condition A and condition B. The ...
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0answers
18 views

Correction for the number of factors in multi-way ANOVA

QUESTION: Should we do multiple comparisons correction for the number of effects (main effects and interactions) in multi-way ANOVA? I might have failed to find a relevant question, but mostly ...
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29 views

Comparing linear sets of data

I'm trying to validate the use of different sample tubes in a pharma environment. We have an established method with a linear calibration curve and QCs at three concentrations within the curve range. ...
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2answers
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“Mixed model ANOVA with random effect”--is this the correct analysis?

Question about an analysis that was done for a study I'm reviewing: The study compared two methods of taking patient core temperature around surgery at a single center; Apx. N=200, temp was taken for ...
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5 views

2 by 2 within-within analysis of analyte data where the baseline changes

Background: I conducted a physical stressor task on two separate days (Day A and B) and collected saliva samples immediately before (baseline) and after (post-stress) the stress task. In the time ...
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3answers
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Mixed-model ANCOVA using nlme in R: How do I interpret and report significant interaction effects?

I've got a significant interaction effect and I'm unsure how to interpret and report the results. In my experiment, I've got plants planted inside fences to protect them from deer (fence plots) and ...
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Break down a 2-by-3 within within ANOVA into two 2-by-2 within within ANOVA

I have data that may be arrayed as a 2 (Time: A1 vs. A2) by 3 (Difficulty: B1, B2, B3) within-within factorial. But I'm not interested in the comparison of difficulty B2 and B3 over Time. Is it ...
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26 views

Getting main and interaction effects from Bayesian factorial ANOVA in Stan

I am using Rstan to build a factorial ANOVA model with two factors and their interaction. The sample dataset has 2 factors, A (levels A1 and A2) and B (levels B1, B2, B3) and 10 replicates for each ...
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1answer
23 views

Conducting anova based on preconditions? Too many hypotheses?

Can you please help clarify what type of test I should be using - The hypothesis is - where clinicians have rated the participant as x, and the participants have scored above 62 on questionnaire for ...
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17 views

Three-factor ANOVA

I’m analysing a dataset on contents of flavonoids in different parts of a plant (factor A: leaves, flowers, stems), during different phases of plant growth (factor B: vegetation, full flowering, ...
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Is ANOVA appropriate for bounded-like data

my study has one variable with three groups and I'd like to examine the differences amongst these three groups. The possible scores for the first group range from 0-18, while the possible scores for ...
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1answer
14 views

Post hoc analysis after two-way repeated measures ANOVA

I am measuring test performance at 10 different timepoints, before and after drug application. So far I ran two-way repeated measures ANOVA and determined there is a significant timepoint, drug, and ...
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1answer
28 views

Which stats can test differences between two experiments?

I have an experiment to look at habitat preferences of beetles and the effect of competition. In the first test, a beetle is on his own in an arena and I measured the % of time he spends in each of ...
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1answer
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How to interpret a boxplot to check for assumptions?

This boxplot shows 5 different forms of dancing, on the y axis we have the number of injuries. This is an ANOVA model. The question is, what assumptions could not be met according to this boxplot? I ...
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1answer
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How to interpret MANOVA results after adding gender, splitting the file?

I am analyzing my 2x3 between subject design with MANOVA in SPSS at the moment. In the main model, there is 2 IV's and 2 DV's. Result of the test is 1 main effect and no interaction effect. In an ...
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1answer
21 views

Comparing main effects and interactions on the same significance scale

When we collect genomics/metabolomics/proteomics data (many variables) in a between-by-within 2-way experimental design, we are often interested in which variables change differently between groups (...
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39 views

How to model time series and to find corelation between times of events

I have data set that track daily activity of user. User repeat action one or more times during a day. This actions are independent and I want to determine if there is relation between times of events. ...
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1answer
25 views

Use contrasts in a 2x2 ANOVA to test directional hypotheses

I think I have a rather simple question. I have a 2x2 ANOVA and I am both interested in the main effects and their interaction. Usually, I'd simply run the ANOVA (type 3) to see whether main effects ...
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36 views

Time Series of Wound Healing

I am struggling with how to approach my dataset for a meaningful analysis and need help. I am looking at wound healing of sharks over time and have hit a wall with analysis. My data consist of ...
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18 views

Is my data suited for an ANOVA?

I have two types of "media" (surface and sediment). I have six toxin variants "variant". All the toxins originate in the surface water, but I want to know if certain toxins are more likely to ...
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1answer
44 views

Select mixed model same degree of freedom

When I have a two mixed models (lme function) with different df then ANOVA summary shows the p-value of likelihood ratio test as following : ...
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27 views

1 experimental group - 6 control groups: ANOVA or t-tests or something else?

Objective: I want to find out, if a certain machine learning algorithm can select the right 100 stocks out of my stock universe of 2.000 stocks, such that they achieve better combined yearly returns ...
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1answer
43 views

Is it correct to run a mixed model (2-ways anova) on a unbalanced and incomplete design?

I am studying the effect of land use on biomass. I am struggling to find the right model to correctly analyse my data. Data description I have surveyed land use changes in 20 fields for 3 years. I ...
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1answer
21 views

checking normality in repeated ANOVA (residuals vs differences)

If I check for the assumptions of a repeated ANOVA (one IV with 3 measurements) I need to check for the normality of differences. From t-test for paired data I know, I calculate the difference and ...
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0answers
14 views

Correct to evaluate the relation between likert type ratings, response time, and age with repeated measures ANOVA and covariates?

I would like to kindly ask you for your point of view on whether my approach is correct. First I will describe my project, then I will ask a question: I conducted approx. 30 surveys in which 28 to ...
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0answers
23 views

lme4 syntax for random effect nested under fixed and random effects

I have data looking at the performance of thousands of one-vs-all binary classifiers trained for an image recognition task under different conditions. I'm trying to use ...
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1answer
40 views

Analysis of one group of subjects (data provided)

I have one group ($n = 39$) of subjects pre- and post-tested on a continuous variable. I also have a gender variable coded $0$ and $1$. I was wondering how I can analyze this data so to detect any ...
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1answer
40 views

recommended approach for building an ANOVA model

Despite reading several online references, including the full Wikipedia article on "ANOVA", I'm still confused at the recommended process taken to build the most statistically significant linear or ...
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1answer
19 views

Why does One Way ANOVA not have an SSE Term?

For a Two Way ANOVA with two factors A and B, the Sum of Square equation is:- SSTO = SSA + SSB + SSAB + SSE Where, SSTO = Total Sum of Squares SSA = Sum of Squares due to Factor A SSB = Sum of ...