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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repeated measures design vs. MANOVA power analysis

My collaborator and I are building a study where participants will read some profiles that vary for 3 dimensions each having 3 levels (9 profiles in total). For each profile participants will have to ...
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Following a post-hoc ANOVA, how do I write the significantly different superscripts?

If my data is as follows: 1 - 6.480 2 - 8.019 3 - 9.110 4 - 10.580 5 - 11.400 6 - 9.733 7 - 9.750 8 - 7.000 On the post hoc ANOVA the average LSD is 2.526, which data sets are significantly different? ...
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What statistical test is appropriate when the independent variables are binary but tied to multiple sites and the dependent variables has many 0s?

I have a data set of microplastic particles/kg taken from various beaches. Each beach has several binary criteria which are the independent variables of the study. My issue is that in some samples ...
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Which test is suitable for such data? t-test, ANOVA, linear regression?

I have data in the following format: Concentration speed height distance control 1.5 3.1 13.1 0.1 1.9 5.4 13.5 0.2 2.3 9 16.7 0.4 2.7 13.1 21.2 I am confused as to what test I should use to see ...
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Interpreting the results of an interaction plot

I have data on 3 species of fish that we fed 2 different types of food and we measure the eggs they lay (number of eggs are a coefficient, but that's not important for this question). The fish species ...
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What do double superscripts mean in an ANOVA table of 'ad hoc' results

What is this alphabet (a,b,c) and what does its combination mean in the table? I have read a lot of literature similar to my work and it shows that most of the researchers have used different ...
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Permutation test involving multiple treatment groups where the test statistic is the precision of a single group

In a setting where we conduct multiple experiments in parallel, I am struggling to figure out whether reporting the significance of the precision of the measurements from a single experiment is a ...
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Replicability metric using a permutation test

I have been using a metric that is (effectively, under the hood) running a set of permutations tests, and then reporting a summary. I'm trying to unpack this metric and struggling to figure out if it ...
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Unequal sample sizes in 2x2 between-subjects ANOVA

I have a 2x2 between-subjects design consisting of Gender (Male, Female), and Relationship status (Married, Single). The DV is completion of a certain behaviour (Yes, No). I plan to use SPSS. I plan ...
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Picking variables to merge and create graphs/maps

I am doing a university coding project on my geography course. I am using r studio and have been given data sets in which i need to use r to make tables, graphs and maps so i can then analyse the ...
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Design matrix for getting desired contrasts in 3x3 design with 2 controls

We have nine conditions in our study (two category factors each with three levels; A: a1, a2, a3; S: s, c1, c2). I did two-way ANOVA; however, we are interested in a more nuanced question. c1 and c2 ...
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ANOVA vs Chi Square Test to compare one independent and one quantitative variable

I believe I understand the basics of chi square test and ANOVA but not confident enough to make a decision on which test to apply or whether both tests can be used. I have a categorical variable: ...
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Type III ANOVA in a crossed interaction showing significant main effect

Given a crossed interaction: ...
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Is two way mixed ANOVA the correct statistic to use in this case?

I have a statistical question regarding which analysis to use. I am pretty new to statistics and r, which I use for the statistics. I have 2 groups treated with different medical drugs (Grp1, Grp2). ...
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Analysing a small data set with lots of zeros? Dependent variable is (semi?) continuous, one fixed (categorical) factor

Hoping to get some advice for choosing an appropriate model for my data. I have a small data set looking at the level of a particular protein (heat shock protein 70) in individuals exposed to ...
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In a 1-way ANOVA, is the square-root of the coefficient of determination the intra-class correlation?

The actual question I mean to ask is if the square-root of the effect size is the intra-class correlation (ICC). When the 1-way ANOVA test is viewed as a bivariate analysis between a categorical ...
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How to compare ANOVA results from multiple data sets

I am trying to find out if there is an age-education category difference between people in the number of votes which they use while voting with a multiple vote voting method. Basically, I am trying to ...
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Dunn's post-hoc Test after Kruskal, 'which one is more effective?' after significant difference

Dunn's test yielded the result that there is a significant difference in revenue between group 1 and group 2 after Kruskal. In classic one way ANOVA case, if the result is same as above, you see ...
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Repeated Measure ANOVA in R?

I am trying to run stats on work information and I am hoping for some help. I currently have a project with just a control, and one treatment that is replicated throughout a block. I am wanting to see ...
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Should I adjust the signigicance level, when deciding on running type2 ANOVA based on interaction test?

I have a 2-factor experiment: A (2 levels) and B (6 levels). The factors may likely interact. The experiment is unbalanced, thus type-1 sequential ANOVA makes no sense, as I don't want to care about ...
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qqplot result and normality for ANOVA

The independent variable is promotion, and it is assigned to 3 groups. The dependent variable is sales revenue. I have 172 observations of sales revenue for promotion group 1, 188 for group 2 and 188 ...
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Fitting the most appropriate model for the data

To compare 4 detection machines and also the performance of 3 scientists, the amount of gold within a chemical substance (of fixed weight) was determined by each scientist using each machine. Two ...
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I’m trying to find the association between 2 variables by conducting a statistical test

My two variables are sex (male/female) and body mass index (BMI). I have a data set of 194 participants. Sex - 107 males (55.15%) / 87 females (44.85%) BMI - 23.88 +/- 5.03 I have no idea which test ...
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Regarding the type 2 or 3 ANOVA, does the analysis via model reduction correspond to LRT and via contrasts - to Wald approach?

I noticed, that in R we can obtain type 2 and type 3 ANOVA in many ways in unbalanced designs: For example, for type-2 car::Anova(...type=2), by running anova() over a sequence of models with swapped ...
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Is there any formal proof that in R type-1 anova() run twice on 2 models with switched terms equals type-2 (looking at the last entry)?

I observed something interesting to me. Let's assume that I have an unbalanced, additive model (no interactions) with 2 terms. When I swap the order of the two terms and run type-1 ANOVA over them, ...
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Why do we need to model lower-order effects in models with interactions?

I recently saw a paper with a four-way interaction. That already is difficult to interpret (maybe if you have 1 or more categorical variables but definitely near impossible to interpret if all ...
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ANOVA or ANCOVA? I have a control variable

In my study, I am analyzing 4 groups, as it is a 2 (primed or not primed) × 2 (high efficacy or low efficacy) experimental design. I am planning on using ANOVA between-subject analyses to test for ...
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Summaring post hoc differences of means for several groups

I have 5 groups with unequal variances. I used a Welch's ANOVA and then a Games-Howell post-hoc analysis to find the pairs that have significant differences. I have a large number of samples in each ...
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What to use for nested subjects with repeated measures, ANCOVA or LME or even SEM?

I have a dataset like: I grouped the subjects based on their initial depressive mood (first step (pre-treatment) of repeated measures level) as 1 low, 2 high. I have two conditions (1 control, 2 ...
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Mixed ANOVA that gives individual group p-values like Pair-wise T-test

I have a dataset with 2 two-factor independent variables: Dosage(Treated, Untreated) and Target(Target1, Target2). With one continuous dependent variable. Treatment is within-subject of Target. I'm ...
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Multiple mice (subjects) grouped by genotype (condition) with multiple measurements per mouse

I am trying to analyze fertility data for a cohort of mice with several different genotypes and I am stumped. 3 mice have genotype A, 3 have genotype B, and so on. Each mouse has several litters over ...
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T-test with replicate measurements, how to quantify error in the measurements?

I want to compare two tools, A and B. I use tool A to measure 10 very different objects, making 5 repeated measurements for each object so I can record an accurate value. I also do this with tool B. ...
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Meta Analysis (metafor in R): Difference between Mixed-Effects Models that have an intercept and those who don't? [duplicate]

My question is more theoretical, less code related. I am trying to enter some moderators to rma.mv() , my moderators are: 1 factor with 4 levels. Call it "F&...
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Is there anything like a two-way ANOVA but for continuous independent variables and a nominal dependent? Also, alternatives to logistic regression?

I want to determine the interaction between two of my continuous (scale) independent variables on the one dependent variable, which is dichotomous (cases are coded as 0 and 1). I was going to use a ...
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Would zero "t-ANOVA" scores imply zero mean differences?

I apologize for the noticeably contrived term "t-ANOVA". It is not really a Student's t-test at least because I am not necessarily assuming a t distribution, but it was a source of ...
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Why is anova not significant when analysis of the str error multiple regression model suggests that it is? [duplicate]

I'm a bit confused as the output of my model in R. I have built a generalised estimating equasion glm model aiming to see the effect of time (here coded as timestrat) on a variable called new1804. I ...
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Why is ANOVA non significant when 95% confidence interval of coefficient is for glm model in R?

I'm a bit confused as the output of my model in R. I have built a generalised estimating equation glm model aiming to see the effect of time (here coded as timestrat) on a variable called new1804. I ...
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Does linear mixed-effects models have an advantage for specifically cross-over effects?

I have not read this anywhere but what I think is mixed models have some advantages (against other methods such as ANOVA) for cross-over effects since they treat individuals differences (intercepts) ...
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gls with ML not working so I can't find the best model

My question is close to this one which wasn't really answered: https://stackoverflow.com/questions/66571314/gls-with-arma-terms-not-working-for-one-combination-of-terms I am running models to ...
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Crossover study design and statistical method (ANOVA or Linear mixed-effects models)

I have a crossover study dataset. I would like to conduct a linear mixed-effects study. What are the pros of LME models over ANOVA, but, for specifically crossover studies. Thanks in advance!
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Confidence when "sorting" multiple samples by mean?

In a one-way ANOVA, we test if the mean is different amongst multiple groups. The results of this might not be super useful when testing a large number of groups, because we only get a confidence ...
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What kind of analysis should I use for a meta-analysis comparing data from several other studies?

I am planning to do a meta-analysis across several previous studies. For each of the studies, I comapre the EEG waveform data (mean amplitude) within 2 specific time slots (early and late), in two ...
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Need guidance for comparing dichotomous data and Likert scale data

I am comparing a job satisfaction survey tool and a leadership questionnaire. One has Yes, No, Uncertain answers and the other one is a 5 point Likert scale. What I am specifically trying to do is ...
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How do I interpret graphs of residuals to check if the assumptions of lm() / anova() are met?

I need to run a one way ANOVA on some data (water_content) from 3 treatment groups (Water), but am struggling to interpret whether I need to transformation the data to make it appropriate for my lm() ...
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How do you calculate F-value for three groups, given only the mean and standard deviation in Python

I am learning about power analysis for different scenarios in Python, e.g. for three groups (assuming equal sample in each group). I've seen videos demo for SPSS and other softwares, where you simply ...
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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 ...
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Is mutifactorial ANOVA the right test for this?

Dependent variable: Volume (mm^3), non-negative Independent variables: Patient 2 levels (sick vs healthy) age 6 levels (in age bins e.g., 31-40, 41-50...) BMI 4 levels (Underweight, Normal, ...
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Non-orthogonal Nested ANOVA

I am running a nested statistical analysis of variance on a field study I preformed. Unfortunately due to the conditions of the field it is non-orthogonal nested design where the number of sub-factors ...
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Nonparametric ANOVA for simulated data

I have some simulated data and I want to test whether "group" has an effect. The data are from a Weibull distribution. because the data are simulated, I can determine sample size, however ...
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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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