Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

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

108 questions
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Two-Way Repeated-Measure design with lme4

I would like to model a treatment effect in two different groups, controlled for some co-variates (like age and education), and I assume that a two-way repeated-measure Anova would be the right approach - if yes, I have some questions on how to…
Daniel
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Unbalanced two-way ANOVA in R Studio

I have a dataset that is unbalanced. I am testing how temperature and the size of a carcass affect the development rate of maggots. The duration is the time spent in a particular development stage of the maggot. I found the higher the temperature…
Kerry
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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 installation of new technology (version 2). Due…
Numbermind
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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 leaves, flowers, stems), which were obtained from…
Fee
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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 product $$y = (\iota_T \otimes I_H)\mu + (I_T \otimes…
Jesper for President
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Are these factors considered random or fixed factors?

I am in a little bit of a mix right now regarding this scenario right here. Assuming I have a 2x3 design, looking at the effects of: Two mood-inducing conditions: Happy Neutral 2.Three levels of task difficulty: Easy Moderate Difficult I wish…
Ang Jit Wei Aaron
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Can I use omega squared with unequal sample sizes (two-way ANOVA)?

I need to compare means of 4 groups (2 categorical predictors and 1 continuous outcome variable). The homogeneity of variance assumption is tenable. However, due to the non-normal distribution and unequal sample sizes (different number of people in…
Draško Kašćelan
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What is an accepted equivalent of non-parametric version two-way ANOVA in R package?

I use R for my statistical analysis. I want to analyse a kinetics experiment that involves measurement over 3 time points with control, genetic background 1, 2 and 3. Can anyone suggest a test and how to arrange the data for that particular test?  I…
Sudip Das
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No value or "."returned for Mauchly's Test of Sphericity in SPSS

I am learning how to do a Two-Way Repeated Measures ANOVA in SPSS but when I try to check the Mauchly's Test of Sphericity Significance value it only displays a single decimal point. It is also missing the Approx. Chi-Square value. The experiment…
Deepend
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Reconciling wildly different $\chi^2$ independence test results (bootstrap clustering)

I have some data that should be randomly assigned to treatment $T$, and am running some tests on observables to give evidence that this is indeed the case. Let's focus on an outcome I'll call $X$, which is discrete, so the most natural test of if $X…
MichaelChirico
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ANOVA on percentage data

I am confused about when I can and/or cannot run an ANOVA on percentage data. MY situation is as follows: I have two separate treatment groups (T1 and T2). Each of these treatment groups receives 1 of 3 drugs (D0, D3, D30) only once. My DV is muscle…
AdrSpec8
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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/little watering and fertilizer/no fertilizer). One…
Deschain
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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 are different. The trouble is, each population has two known…
thedu
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Interpreting interaction from two-way anova table

I've conducted three pairwise comparisons of variables and the results were as below: Analysis of Variance Table Response: Y Df Sum Sq Mean Sq F value Pr(>F) Dataset$A 1 1140.57…
jypark1
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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 IV2) with repeated measures on both factors, and I gather that one needs to account…
user3050269
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