# Questions tagged [two-way]

For statistical models or methods used to study the effects ow two variables simultaneously, see https://en.wikipedia.org/wiki/Two-way_analysis_of_variance

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### Two Way Anova with Heteroscedasticity

I'm trying to run a two way anova test but the homoscedasticity condition is not met. My analysis is not balanced and I have over 3000 observations in my sample. Is it okay to proceed even if the ...
21 views

### How to interpret results of a GLM from a double factor experimental design

I have an experiment with two factors "Enzyme", and "FeedMixture" which has 4 different levels. "FeedMixture", is a variable of type factor. Below I simulate a response ...
1 vote
28 views

### Help needed in recreating ANOVA test results from study

I am aiming to recreate ANOVA tests as part of Study 1 from the following research paper related to some psychological factors: https://doi.org/10.3389/fpsyg.2021.738447 There are altogether 80 ...
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### Should I use one-way or two-way anova?

There are eight groups of treatment with different concentrations and different. Initially, we thought about using two-way ANOVA with the factors being 1. the type of experimental setup and 2. the ...
44 views

### Two-way ANOVA help

I am measuring the differences in fungal abundance in different stages of grazing and depth so I have tow factors (grazing intensity and soil depth) My main effects are all significant but so is the ...
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### Contrasting results between ANOVA (car) and emmeans

I conducted an experiment involving two forest plots: one that experienced a fire and another that remained unburned. Each plot was further divided into two regions: the edge and the interior. My ...
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### Appropriate design for two experimental conditions and incomplete blocking

I'm planning to perform an experiment in which I will be assessing the role of two experimental variables (A: 6 levels, B: 4 levels) on a defined outcome which, however, might be affected by external ...
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### Anova model assumptions. How to go by?

I have a data frame that contains a continuous response variable measured on different species, at different elevation and month of sampling as explanatory variables. I want to analyze how the ...
21 views

### Robust ANOVA t2way unequal sample sizes?

I have some parameters that I would like to analyze with a two-way ANOVA. The treatment groups have unequal sample sizes (n=9, n=36, n=36, n=36) and the data do not fulfill the requirement of normal ...
366 views

### Confusion about Two Way ANOVA test vs Chi-square test for independence. Which one to use here?

A certain drug is claimed to be effective in curing cold. In an experiment on 500 persons suffering from cold, half of them were given the drug and the other half were given the sugar pills. Patients' ...
1 vote
32 views

### How to analyze multivariate data that comes from a 2D design space?

I'm analyzing a set of biological samples. Each sample is linked to a specific carbon and nitrogen concentration, representing the 2D (experimental) design space I referenced in the title. I've ...
23 views

### What's the relationship between this two-way hierarchical table and the stacked barchart?

I have the first impression the hierarchical two way table, it throws out the gasoline, it creates a new category called "other food at home" How to reconcile the numbers under Food at Home ...
24 views

### What is the best post-hoc test to use after a two-way anova has shown there is only a significant effect when including 0 as a factor level?

I have two factors: A and B, and a response, y. For factor A I have 3 levels: 300,400,500. For factor B I have 3 levels: 0.5, 0.6, 0.7. I carried out an experiment with each combination of these two ...
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### Confusion for 2-way Anova in 2x2 experimental design with planned comparisons

I am really confused regarding 2-way Anovas. I think I did not understand something properly. Let's say I have a 2x2 experiment design with 2 factorial variables (For the sake of an example let's say ...
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### Running an ANOVA (repeated measures two-way ANOVA) with unequal sample sizes

We have four sites, within each site we tagged 40 mangrove individuals and measured their height every 3 months for 2 years. We have three mangrove species present within each site but it is mainly ...
67 views

### Factorial ANOVA with missing cell

I would like to run a two-way ANOVA with interaction between the two factors. I did an experiment with two treatments: Treatment 1 has four levels (A,B,C,D) and treatment 2 has three levels (I, P,F). ...
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### Kruskal-Wallis as a non-parametric alternative to 2-way ANOVA?

I'm a master student currently working with taxonomy and cultivation of wild edible mushrooms. In my experiment, I'm evaluating the effect of 4 distinct solid culture media and 4 temperatures on the ...
45 views

### Binning to create categorical variable to be used as a factor in ANOVA

I measured students' motivation using a likert type questionnaire and I want to check its effects on some dependent variables in a factorial ANOVA analysis. I wonder if it is okay to create ...
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### Is it still a factorial ANOVA when one independent variable is a continuous or ordinal variable

Let's say in a research study, participants receive training, and I measure their learning gains before and after the therapy. At the beginning of the study, before the training, I also administered a ...
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1 vote
315 views

### Mixed model with two fixed effects, with repeated measures for only one of them

I am using linear mixed effect models to study the effect of a physical therapy treatment on two different populations of patients (Adolescents and Adults). The treatment is the same for both ...
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1 vote
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### Non parametric 2 way anova

In my dataset, there are two distinct species, each with three unique treatments. My objective is to investigate whether there are any significant differences among the various species and treatments. ...
1 vote
811 views

### Reporting post-hoc test with letters (two way anova)

i am testing soil chemistry in soil that has been samples in fields subjected grazing. So two levels ( grazing treatment and soil depth). I have used a two-way ANOVA after testing for normalisation ...
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### Power analysis for two-way repeated measures ANOVA

I am trying to run a post-hoc power analysis on a previously conducted study, in which the results were analysed through a two-way repeated measures ANOVA (I used a 2x2 within-subjects design). ...
1 vote
57 views

### Should I use a two-way ANCOVA or three-way repeated measures ANOVA on my data?

I am trying to run a two-way ANCOVA on data from a multi-crossed design, looking at the effect of 4 treatments on the decay rates of 2 DNA target concentrations in moving water over time. Mesocosms ...
63 views

### Statistical test for two factors (each multiple levels) and repeated measures

I wondered what statistical test to use in the following case: one categorical factor/condition with three levels one ordinal factor/condition with three levels one numeric response variable a small ...
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1 vote
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### How can I correct for multiple comparisons in two-way non-normal data (without using Bonferroni)

I'm struggling to carry out statistical analysis on my cell viability assay. The assay is widely used (it's called resazurin or alamarBlue assay), but I don't think it is analysed correctly in the ...
1k views

### Two-way mixed repeated measures MANOVA in Python or R

I compare three groups: A control group Two different clinical populations They are subjected to 6 different types of stimuli, several times each (repeated measures), and 5 dependent variables are ...
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1 vote
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### Residuals of a 2x2 between-subjects factorial ANOVA are not normally distributed

Dependent variable: Emotional impact – measured by two ordinal variables (questions) on a Likert scale [1 (Least) to 10 (Most)] A composite mean score of the two variables was created named ...
615 views

### Two-way ANOVA (2x2) interpretation for non-significant values

I'm a statistics beginner and for my research, I'm looking into the effect participants' body image (positive/negative) and an advert model type (thin/plus-sized) have on participants' view of their ...
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### Analysis of variance with two empty groups: alternative?

I have treated a species with two treatments: salinity: five different concentrations a pollutant (control and two different concentrations) organisms grown with the two lowermost concentrations of ...
98 views

### Analyzing data from a pre/post study when ANCOVA isn't possible and the denominator may be zero when calculating change scores

We have conducted an experiment on an animal model of a psychiatric disorder using a pre-treatment (PRE)/post-treatment (POST) design with two treatments resulting in 4 study groups (No treatment, ...
721 views

### Two-Way anova assumptions not fulfilled

My task is to determine whether two different categorical variables (residence location (city/rural) & residence size (small/medium/large)) have a connection on one numeric variable (residence ...
242 views

### Is a 2-way ANOVA immune to Simpson's Paradox?

Sometimes continuous data is of the type that would result in Simpson's Paradox findings if groups were simply aggregated. (See, for example, "Example #2: Baseball" on this page https://www....
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### Should I perform a Post Hoc analysis if I get no significant interaction in two way anova?

Hello all! I am performing a two-way ANOVA for an experiment I am doing but I reached a concern. I saw no significant interaction effect, still, I performed a post hoc TUKEY test and got significance ...
595 views

### the two step approach

I have a continuous variable which is not normally distributed i want to transform it to normal using the two step approach method in the link below: Abstract This article describes and demonstrates ...
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1 vote
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### Separate anovas or 7 way manova?

I have 7 independent variables and two dependent variables which I think I should run 7 way manova, but this method is to complicated to compute, is running separate anovas for each dependent variable ...
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560 views

### Odds ratio for an $I \times J$ table

I am trying to find a general expression for the odds ratio in a two-way table. I know for a $2 \times 2$ table odds ratio can be expressed as: $${\rm OR} = \frac{\pi_{11}\pi_{22}}{\pi_{12}\pi_{21}}.$$...
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### Why is there no panel quantile regression with two-way fixed effects yet?

I have been learning the quantile regression model recently, and my understanding is (possibly wrong) that quantile regression is essentially extracting the subsamples corresponding to a certain ...
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1 vote
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### Question on what is being repeated in this repeated measures ANOVA

I am replicating a two-way repeated measures ANOVA in a journal for practice. There are: One dependent variable density (I chose one from multiple dv presented in ...
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1 vote
2k views

### Event study / DiD with panel data and repeated treatment in different years for each country

I have an unbalanced panel dataset with approximately 30 countries from 1980-2000. I would like to study how political uncertainty measured by close elections affects a certain continuous variable $Y$,...
965 views

### Post-hoc test of two-way permutation ANOVA

I have a 2x2 study design to test the interaction between two drugs, with a single variable outcome. The data are very much non-parametric and it seems that a good alternative to the traditional two-...
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2k views

### Post-hoc test for PERMANOVA (adonis2) of a single variable (vegan package)

I have a 2x2 study design to test for the interaction between two drugs (i.e. with or without drug1 and/or drug2), with a single continuous outcome for each combination. The data are unbalanced and ...
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### Differences between nested ANOVA and two-way ANOVA, without a repeated measures structure and a small number of levels per factor

My question is rather simple, and it's not so much about R, but about how to analyse a very simple dataset. I have 6 sites, and 2 ecosystem type (3 sites per ecosystem). From each site I have 3 ...
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### Two-way ANOVA: does the interpretation of a significant main effect apply to all levels of the other (non sig.) main effect if no interaction effect?

I need clarification re how to interpret the results of a two-way ANOVA modelled with an interaction effect. My results suggest that the interaction effect is not significant, and that only one of my ...
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1 vote
693 views

### What Statistical test would be most appropriate for comparing death counts by age in two populations?

I am not a statistician by any means, and am new to this. I have "patient" level data that has a persons death status, age, and gender. I want to compare it with the general population ...
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1 vote
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### How to control the family-wise error rate testing simultaneous hypothesis in two-way Anova?

I guess explaining with an example would be best. Let's say we are researching which type of fertilizer and planting density produces the greatest crop yield in a field experiment. We assign different ...
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1 vote
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### Two-way ANOVA test in R

I have some measurements of 14 animals in control group and 12 animals in treatment group (10 weeks old). After 4 weeks we repeated those measurements but most of animals have died. I left with 5 ...
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1 vote
178 views

### How to calculate the error terms in mixed ANOVA?

I recently came across this question and just couldn’t figure it out. I have to derive a ANOVA table from the following data: B1 B2 B3 A1 35 32 29 A2 29 28 27 A is a between-participants IV with 2 ...
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### Does two-way ANOVA still works fine with unequal sample sizes?

I want to test if installing a new technology (with two different versions) can reduce water waste. I'll test the following: no installation (control), installation of new technology (version 1), and ...
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