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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One-way ANOVA and Two-way ANOVA p-value

I have a dataset with 270 observations, 90 for each group (A,B,C). With One-way ANOVA I'm testing if there is a difference in my variable y depending on each one of the groups A,B and C. ...
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7 views

Number of planned tests using Bonferroni for a two-way ANOVA?

I have a two-factor study with factors A and B. There are 4 factors of A and 4 factors of B, with a replication of 3 for each. $$a = 4, b = 4, n = 3$$ After looking at the ANOVA table, I can see that ...
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27 views

How to estimate the source of variation in R? (For two-way ANOVA)

In my laboratory we used a statistical software, but now we are using R for the statistics. Using the statistical software, after a two-way ANOVA, a table with the results includes "Source of ...
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40 views

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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7 views

Different Results betweeen Pairwise subsampled by Factor OneWay Anova and Two-Way Anova

I have been testing 4 different groups, Control/TestNotOpen/TestNotClick/TestClick on a continuous variable: Withdraw Value. I have a factor to consider: policySegment which can assume 3 values I have ...
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14 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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11 views

Individual effects in two-way ANOVA in R

I have a 2b x 3w factorial design with a continuous DV. The between factor is 'gender' (so 2 levels), the within-factor is the 'group' (3 levels). I have measures for each individual (male and female) ...
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7 views

two-way repeated measures ANOVA and long_db format

Good morning everybody Here I show a dataset I'm performing a statistical analysis on. Aside the meaning names of most remarkable variables are indicated: ...
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74 views

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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1answer
30 views

Is normality assessed in each individual group or for the entire dataset in repeated measures ANOVA?

This is probably a stupid question, but somehow I got very confused and so far I could not find a clear answer (there might be no clear answer). I have residue data in 4 different plant matrices (eg ...
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33 views

Two ways ANOVA does not show the interaction between the variables [closed]

I am doing a two-way ANOVA and I want to examine the interaction between two variables. The variables are the following: STS (Sign language knowledge) and Hearing (if they are hearing or deaf). Both ...
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1answer
154 views

How to calculate sample size for blocked-design two-way ANOVA?

Does anyone know of a good online calculator or at least a good paper that details how to calculate the needed sample size for a blocked-design two-way ANOVA experiment? I've seen a ton of references ...
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15 views

Framing the hypotheses for a two-way ANOVA

[Table showing the decrease in weights(in kgs) for 9 people taking into consideration 3 types of diet and different time periods(in number of weeks)] It is asked to apply the appropriate ANOVA ...
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17 views

Why not include the interaction in the partial eta squared of a principal effect?

The partial eta squared of the principal effect of factor $A$ in a two-way ANOVA is defined as $$SS_A\over SS_A+SS_{error}$$ While I understand perfectly what this represents, it would somewhat make ...
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1answer
35 views

Two- or One-Way Anova?

I am having a question regarding a statistical analysis I am conducting. Let's say I have a continuous variable that I measure (Plant Weight) and I have 2 factors with 2 levels (sufficient watering/...
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1answer
25 views

Which ANOVA should I use?

Let's say I have a problem where there are two distinct groups, and within each groups, there are two more groups, leading to a total of four groups. So it's something like this: I want to run five ...
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2answers
61 views

one-sided t-test after a two-sided t-test?

I have two groups and I conducted a two-sided $t$-test. mean group 1: 3.79 mean group 2: 4.07 $p$-value: 0.0081 The $p$-value is less than $\alpha$ = 0.05, hence, I can reject the null hypothesis of ...
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26 views

How can I get LSDV estimator of a two-way dynamic panel model?

I am now trying to explain a dynamic panel data model as follow: $y_{it} = \alpha y_{i,t-1} + x_{it}'\beta + \mu_i + \lambda_t + \nu_{it}$ Here I want to compute its LSDV estimator $\tilde\beta$, ...
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13 views

How to test/ interpret two-way or three-way interaction effects with IVs and moderators?

I have a question regarding testing/ interpreting two-way or three-way interaction effects with IVs and moderators. I have 3 IVs (categorical: first has two levels, second has 4 levels, third has 6 ...
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1answer
23 views

Can I do a hypothesis test to see if two populations are different if there are known subpopulations within the data?

I have a continuously variable output (diffusivities) that I have measured from two different populations (say "Case 1" and "Case 2"), and I am trying to see if the two populations ...
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9 views

Estimated means between 1-way anova and 2-way anova don't match up

I have a study with two explanatory variables, one with 2 levels, and another with 3. However, only 5 of the 6 cases are observed. Illustrated: . 1. 2. 3 A X X X B X - X I have decided to look for ...
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21 views

Calculating alpha level for Bonferroni

I have 4 null hypotheses. I want to conduct 4 two-way mixed ANOVAs (one between-subjects factor and one within-subjects factor) for each of my 4 dependent variables. I will use the same between-...
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1answer
23 views

My Design defines the Hypothesis test?

a conceptual question appear in my mind and i need help, in pratical therms, whats defines the statistical test its my hypothesis and my experimental design ? Using this example, if i am interrested ...
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26 views

Error function in aov()

To the point, my question is How to use the Error function in aov()? What calculation has been performed in Error function? To examine the effect of treatment, I set the three groups (Group: Control,...
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45 views

pureErrorAnova(alr3 package on R) would work for two-way factorial anova

I have a balanced 2x5 anova factorial which 4 replicates each group. I'm trying to check the Lack of fit and I came accross the pureErrorAnova - alr3 package (Im using R software). My independent ...
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1answer
81 views

Can we use `two way anova` when factors have interaction?

You should have independence of observations, which means that there is no relationship between the observations in each group or between the groups themselves. Above sentence come from https://...
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93 views

Two-way or three way repeated measures ANOVA with replicates

I have tried to read some papers about two-way ANOVA and repeated measures ANOVA but I just get more confused the more I read. I have a BACI study design where I have investigated 12 stations. I have ...
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1answer
47 views

Is it apporpriate to use two way ANOVA test if I have paired data linked to single individual?

I am new in statistics. I wanted to do some statistical test to determine whether there is a difference between two samples and over the individuals. So if I have data that looks like this: ...
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2answers
49 views

Interpreting interaction from two-way anova table

I've conducted three pairwise comparisons of variables and the results were as below: ...
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1answer
49 views

Kronecker product for two way error component model

The two way Error Component Model defined as $$y_{it} = \mathbf x_{it}^\top \beta + \mu_i + \lambda_t + v_{it}$$ for $i=1,...,H$ and $t=1,...,T$ can be written in matrix notation using kronecker ...
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2answers
671 views

How to approach unbalanced data with unequal sample sizes for comparing means

I have a data with a continuous and two categorical (population and sex) variables. I want to test whether the means among the groups are significantly different. However, this is not an experimental ...
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1answer
33 views

Two way ANOVA when one independant variable is not Categorical

I am doing a test on doctors' training level and the number on duty. One IV is training level, the other IV is the number of doctors on duty. The DV is the number of patients seen. There are two ...
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1answer
96 views

Two way analysis of binary data (repeated)

I have a data set that is measuring a yes(1)/no(0) outcome across six time points and under two conditions. We have 15 participants that completed all time points under the two conditions. Disclaimer;...
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1answer
94 views

R survey sackage method for replicating SUDAAN proc crosstabs SEROW [closed]

I have been using SUDAAN's proc crosstabs to generated weighted crosstabs, percentages, and standard errors for counts and percentages. I'm trying to replicate this functionality in R and have gotten ...
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1answer
32 views

What is the difference between the measurement, and within subject factor fields is in SPSS (two-way repeated measures ANOVA)?

First, I am sorry if this seems very silly, but this is the first time I do any statistical analysis. I did a study with 10 subjects and I have a couple of questions regarding the statistical ...
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1answer
195 views

Comparing proportions of two samples in time

I am trying to compare if the proportion of one bird subspecies in a roosting area is different now from over 20 years ago. My dataset looks like following: -In 1996 birds were counted at a ...
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1answer
88 views

Homogeneity of variances but non normal residuals of a two way ANOVA

I have a problem, actually two. I am doing a bunch two-way ANOVAs and some of them can't fullfil the assumptions, no matter what I transform the data to. Question: Does there exist a suitable non-...
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1answer
2k views

Dummy variables in two-way ANOVA

I do not understand how to use dummy variables and the statistics underlying them. I don't need to apply this or use it in SPSS or any software. I do know that they can be used for categorical ...
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120 views

Two way ANOVA with percent change

I have two groups of animals: "active cycle" and "inactive cycle". Within each group, there are two groups: "control" and "treated". I measured the levels of a specific receptor for each animal in ...
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2answers
247 views

A two mixed ANOVA showed no significant interaction, but showed a statistically significant main effect of time, Do I need to run a paired T-test?

I did a mixed ANOVA with one within subjects factor with two levels 'time' and one between subjects factor (control + intervention). Its a comparison between INT or CON on scores pretraining and ...
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1answer
332 views

Help in Two-way ANOVA with Significant Interaction

I got the following results for an experiment of fermentation to produce Butanol: ...
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609 views

r - How to use Aligned Rank Transformed ANOVA for 2x2 non-normal data?

I'm a complete novice to stats and r so kindly bear with me. I'm testing to see if the moisture content in two plants (p and s) is affected by heat (cold and warm). The 2x2 factorial data mandates a ...
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1answer
126 views

Are these the correct residuals to test for normality for a within-subjects 2-way anova?

I have data of an experiment where subjects performed a task under 4 conditions (A1B1, A1B2, A2B1, A2B2, where A1/A2 are the levels of factor IV1 and B1/B2 those of ...
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2k views

Understanding, reporting and post hoc testing a 2x2 Mixed ANOVA

I one dependent variable, one between groups independent variable (intervention vs. control) and one within groups independent variable (time1 vs time2) so I am using a 2x2 mixed ANOVA. These are my ...
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346 views

What statistical test should I use for moderation?

I am hoping to test an interaction effect, though being new to statistics/quant research in general, I am a little unsure as to which test would be most appropriate. I have read around using ...
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1answer
537 views

Unbalanced Two Way ANOVA

I am attempting to finish my stats on my Master's thesis and am having difficulties with which statistics test I should be using, and how to go about doing so. I have collected chl-a samples at 15 ...
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1answer
511 views

Biostats two way anova in R boxplot visualisation

I am having a problem analyzing some data from a recent experiment in R. The experiment was balanced with 5 replicates in each group. It included two factors (plant type and leaf age) with 15 ...
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46 views

Significant interaction in Mixed-design 2-way ANOVA. How to correct for multiple comparisons?

I have conducted a mixed-design two-way ANOVA (between subjects variable : 2 levels; within subjects variable : 8 levels). I have a significant main effect of between and within subject variables and ...
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1answer
72 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
99 views

Two way ANOVA, no difference between tests based on type I vs type II sums of squares

I'm learning about two way ANOVA possibly with interaction. I'm following this tutorial http://www.sthda.com/english/wiki/two-way-anova-test-in-r This is their code. ...