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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How to run an ANOVA when there are multiple repetitions

I have a 2x2 repeated measures ANOVA (2 factors each with 2 levels). In addition each subject completes each condition multiple times (5 repetitions). So for example I would have Factor A, level 1 ...
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2x6 repeated measures ANOVA interaction and main effects question

Currently I'm graduating and I'm finishing up my master's thesis as we speak. It's a study about the effect of hand positioning on response time. I'm submitting my data to a 2x6 repeated measures ...
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T-test or repeated measure ANOVA?

I am a Phd student in neuroscience and not so knowledgeable in statistics. I have done an experiment and am not sure if i should use repeated measures ANOVA or independent T-test. The experiment is ...
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Dealing with missing data in Repeated Measures ANOVA

Hi :) I have a data set of comprised of: different subjects, each tested within subject (three time points) on a continuous scale, on various (unrelated) dependant measures. Some of these subjects ...
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73 views

Small sample size - repeated measure ANOVA or something more simple?

I have data from an ecological study on wasp abundance and diversity across a forest which I am trying to analyse appropriately. We have abundance and diversity data from ten locations that were ...
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Bootstrap comparison of group means instead of ANOVA/tukeyHSD

I have several groups (~30, >100 data points per group) and would like to see if there are differences between the group means and where. Both ANOVA and Kruskal-Wallace say yes and I'd like to see the ...
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14 views

Mean comparison multiple groups **NESTED ANOVA**

I’m not sure if this question has been asked before as I don’t know how to phrase it in a search. But essentially I’m trying to test if there are differences between store locations that have trained ...
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24 views

GLM: Is it necessary to include lower-order interactions when testing higher-order interactions

It appears to be a general principle that one should include all main effect terms when modelling interactions in (generalized) linear models (as argued here, for example: Including the interaction ...
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aov() and lme() give completely different results in analyzing repeated measures

I have data consisting of two measures per subject (variable score, measured at Day 0, and Day1 per each subject). There are two groups, and each subject belongs to one of them (variable Group). I ...
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Anova output in R when testing lm() [duplicate]

I am trying to make a simple linear regression to see if my variable "totalssq" has an influence on my variable "hadsa". (my data is "dstatss") Both are quantitative. I made a model with lm() and ...
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Checking linearity assumption and colinearity assumption

Linear regression is equivalent to ANOVA. Do we need to check for linearity and multicolinearity for ANOVA? I have seen that these assumptions are usually omitted for ANOVA but not for linear ...
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Calculating standard deviations and testing the null hypothesis in a biological sample with n = 6

I am doing experiments on the viability of cells after treatment with different amounts of a certain substance. I have split my original cell line into 6 separate flasks at 3 days after unfreezing. ...
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Is there a concern for multiple comparisons when ranking instead of using significance?

Let's say I have many ANOVA tests on the same data using different factor variables each time. Then, I want to rank the F-statistics for all of those tests. Notice that I'm not interested in ...
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ANOVA with repeated identical acquisitions (subject+treatment+tests)

I'm just reviewing an analysis done by an ex-colleague and am struggling to figure out whether it's been done correctly or not. I'm also not sure how to exactly call the model they employed. ...
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2way ANOVA vs. (1way) ANOVA vs. (1way) ANCOVA

Here's my problem. DV: Working Memory (WM) performance IdV:Group (1 vs. 2) IdV: Gender (male vs. female) When I do a normal one way ANOVA with IdV: group and DV: WM_performance, the significance of ...
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How to find the standard error of the covariate coefficient? [closed]

Sorry about having to post this question as a picture but I didn't know how to include all the data without making it look unreadable. I was just wondering if someone could tell me how I would go ...
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12 views

a priori power analysis for ANOVA plus post hoc test

I would like to perform an a priori power analysis to calculate required sample size for data to be analyzed using one way ANOVA and Tukey HSD post hoc test. (I want to determine pair-wise which ...
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20 views

Which effect size analysis is most meaningful for mixed ANOVA

I'm trying to get my head around which effect size is most meaningful for a 2x2 mixed ANOVA for two intervention groups. I have pre and post assessement data (measured at the continuous level) for two ...
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20 views

Nested ANOVA alternative for heteroscedastic data (Nested Welch ANOVA)

Question: Is there an equivalent of Nested -ANOVA for data which fails ANOVA requirement? Is it possible to perform in R? Many thanks, Savani I am doing an analysis of large data set. I have ...
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Repeated measures anova in R

I have a dataset containing percentage scores for 15 participants. There are two observations for every participant, one with an intervention and one with a placebo in a double-blind design. Each ...
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43 views

Model selection: testing the need for random-effects terms in longitudinal data

I have longitudinal data set where each participant was observed for 12 weeks. I followed this paper: Bliese, Paul D., and Robert E. Ployhart. "Growth modeling using random coefficient models: Model ...
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14 views

Two-way ANOVA on mixed linear model in R, homogeneity of variance assumption

I am a bit confused with a two-way ANOVA that I want to perform in R. I have a mixed linear model that I want to perform an ANOVA for: ...
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moderated mediation but no moderation?

I have a 2 x 2 between factor design which I analyzed using an ANOVA. I was hoping for an interaction effect to demonstrate moderation which I didn’t get. BUT then I entered a covariate and now I have ...
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Specific Differences B/T SPSS Grad Packs

I have been using the Trial Version of IBM's SPSS Statistics Desktop v. 24 I would like to purchase the most affordable option that enables a few but very specific features my research requires. ...
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when variances are unequal between groups. (Welch ANOVA in r)

I want to know why the results are different between oneway.test() and gls() I assume the variance are different across ...
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Linear regression summary in R: Standard vs car.Anova

I am running some linear regressions in R. I am dealing with a linear dependent and linear as well as categorical independent variables using lm. So far, I have looked at the output that ...
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How can bucketing a prediction variable make it significant?

Recently, I read a research report that said that "When academic achievement (first-year GPA) was treated as a continuous variable the relationship between academic achievement and emotional ...
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Dunnett T3 test interpretation

i have result from a Dunnett T3 test using package DTK in R. The result do not give me any p-value but only "Diff", "lower CI" and "upper CI". i can understand the difference between groups as the ...
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Repeated measures ANOVA contrasts

I'm running a repeated measures ANOVA with a 3-level DV. Now what I've read is that you only look at the post-hoc test if the within-subject (overall) effect is significant. What about the ...
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Standardized difference of means for multiple classes

Standardized mean difference is very straightforward when you have 2 distributions / groups. How is this metric computed when you have >2 groups? Is there a better alternative to determining the ...
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Predicting viewer's cultural heritage from glmer and lmer versions of formula with different results?

I'm trying to understand why I'm getting different results when comparing anovas for glmer(binomial) and lmer versions of a formula. I am interested in whether a participant/viewer's cultural ...
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Distribution of Sum Square Total and Error in Textbook?

I'd like to check my understanding that there is an incorrect statement in my textbook. Then, I'd like to check my understanding on what is actually true. Montgomery's Design of Experiments textbook ...
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What is an appropriate statistic for this problem

I measured an independent variable, Y, at 4 locations: Y1, Y2, Y3, Y4. I assume Y is influences by 5 factors: A B C D E, and measured them together with Y each location. Therefore, Y1 ~ A1 + B1 + C1 + ...
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Why do we need to check for these two assumptions for ANCOVA but not for factorial ANOVA?

ANCOVA has two additional assumptions as compared to two-way factorial ANOVA. They are (1) independence of the covariate and factor (2) homogeneity of slope. Why don't we need to check them for ...
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A/B test, adequate statistical test for conversion rate analysis

I have the results from an A/B test conducted to assess if the new version of a website yields better conversion rate than the old version. Let's say I have the following entries in the table: ...
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Unbalanced Repeated Measures Anova

First Question: I would like to double check that my code is doing what I think it is doing. I have two independent variables, Previous drilling and Soil Type, that are observational. Simpsons ...
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statistical test in R for normalized time course data

gene time average stdev gene1 24h 1.1 0.01 gene1 48h 0.9 0.023 gene1 72h 0.7 0.01 gene1 96h 0.5 0.021 My data above ...
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Application of Anova/Manova

I have a dataset providing information about head and leg injuries for drivers and passengers . The dataset contains the following variables Head.IC: Head injury criterion(number) Chest_decel: Chest ...
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What is a quasi F ratio and how to compute it in R?

I've been reading this classic study (free pdf) of false memories by Loftus & Palmer (1974) and do not understand their analysis in Experiment 1 (p. 586), particularly— a) the use of subjects as ...
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how to do a repeated measures analysis on my data with linear mixed model in R?

I'm very new to R and stats in general but I think I need to do a repeated measures analysis perhaps using a linear mixed model on my data. Data are behavioural measurements e.g. distance swum for 21 ...
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Which analysis is best for my data with repeated measures and 2 treatment groups?

I'm working in R. I have a data set of 21 fish, roughly half in each of 2 treatments. I measured their behaviour over 10 minutes and want to analyse this to look for changes over time (gradient) and ...
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Unequal Sample Size Effect on Power Calculation

I am new to power analysis and have been experimenting with one-way fixed effects Anova in G*Power (Fixed effects, omnibus, one-way). 1) When dealing with unbalanced design, the effect size is ...
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Express analysis of deviance table as ANOVA

How can I express the following analysis of deviance in an ANOVA table , by hand not with R..
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Anova and contrast

How do we use ANOVA and Contrast to compare multiple dependent variables with multiple independent variables in R. Have watched few videos in you-tube but am really confused. How do I compare ...
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How can I analyze response data that is clustered around the ends and middle of a scale?

I have an experiment where I divide people up in to 4 conditions, give them 100 dollars and allow them to gamble any percentage of the $100 that they chose (50% chance of earning 2.5 as much as they ...
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sample size for repeated measure ANOVA in gpower

I am trying to get a priori calculation for sample size for repeated measure anova in gpower. I put all parameters and got a result. I am not sure if gpower gives a total sample size no matter how ...
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67 views

How to model a 2x2x2 dataset for a 3 way repeated measures ANOVA analysis

I have some data derived from a 2x2x2 experimental design. There are 3 IV's, each with 2 levels. My DV is reaction time (measured in seconds). I've used a repeated measures design (n=10). I have 20 ...
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ANOVA with skewed data

I am doing research on synaptic terminals onto cell bodies in the brain through development. I have three age groups that I have compared on several measures, and I have used a one-way ANOVA with ...
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When to use ANOVA in questionnaire analysis

As part of my dissertation I have used multiple outcome measures to assess pain, sleep, mood and general health in a chronic pain population. I have correlated some of the measures together to see ...