ANOVA stands for ANalysis Of VAriance, a statistical model and set of procedures for comparing the means of groups of related data. 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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Trying a multivariate analyses on time series (with R)

I got measures of one variable (that behaves as a time series) for different conditions (some quantitatives, but mostly are qualitatives). For example, this is a "fake" representative plot of this ...
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11 views

warning message from ezANOVA function in R

I am new to R and I am trying to use ezANOVA to do a repeated measure factorial anova. So I have a data frame named mus.df, which looks like the following (with more rows): ...
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26 views

Is it inappropriate to do a One-way independent ANOVA when one of the levels has only one participant?

I sense this is not a good idea, but am struggling to think of an reason why it is wrong, other than that the assumption of homogeneity of variances would surely be violated. Is there some more ...
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13 views

Multiple Comparisons after an ANOVA

I want to perform a Tukey's HSD after performing a three way anova with blocks as a fourth random factor. I am able to perform the anova using aov(dv~f1*f2*f3+Error(block/(f1*f2*f3)), data=*.txt). ...
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21 views

What is PRINCIPAL HESSAIN Direction Model, how and where can I use it?

I'm a M.Tech student going through my academic project-work, here I have asked to develop a optimal design and a best equation to fit the data for a Leaching, Solvent extraction and Electrowinning ...
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1answer
21 views

Levels or Independent Variables in ANOVA

There are four different types of mobile phones (same brand) that are used as stimuli in an experiment. In the first example, if "mobile phone" is the independent variable in the study, which one ...
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6 views

How to statistically analyze a (ratio/interval) questionnaire

How do we analyze a questionnaire that has multiple items (interval) on a 5 points Likert scale? Once the respondents submit the filled questionnaires, is there a specific procedure to code the data? ...
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1answer
17 views

Tests needed for repeated measures within groups 2*2 design?

I've recently conducted an experiment with two independent variables: musictype and wordtype, measured by response time. 20 participants. I've done a one-way repeated measures ANOVA along with the ...
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20 views

Which analysis is appropriate when there are categorical and ratio variables?

There is a preliminary demographic questionnaire that has items like: age, gender, proficiency level, platform preference, number of hrs/week. In addition, there are other instruments in this same ...
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1answer
21 views

How to perform this ANOVA?

I am interested to know if we have 3 dependent variables, and 2 independent variables, online and face to face, with 2 levels each, as in the example below. The sample size is 30 for each mode of ...
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1answer
29 views

How does the interpretation of main effects in a Two-Way ANOVA change depending on whether the interaction effect is significant?

As far as I can tell this question has never been asked before. There are several questions that touch on related issues, but as far as I can see none of them have provided a definitive answer to this ...
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427 views

If I'm not interested in the interaction, is there any reason to run a Two-Way ANOVA instead of two One-Way ANOVAs?

I mean any reason aside from the convenience of being able to complete the analysis within a single procedure.
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1answer
40 views

How should you fit ANOVA and linear regression models, if the equal variance assumption is violated?

This is my topic for the paper I'm working on for an undergrad stats class. It's supposed to be 20 pages... and I'll be honest, I understand very little beyond the basics and am over my head. From ...
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1answer
32 views

Interpreting a significant 2-way interaction with post-hoc tests

I'm analyzing reaction time data from a repeated measures ANOVA with the following design: Factor 1 (between-group): GROUP (controls, clinical) Factor 2 ...
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5 views

Setting Contrasts for ANOVA in R [migrated]

I've been attempting to perform an ANOVA in R recently on the attached data frame. My question revolves around the setting of contrasts. My design is a 3x5 within-subjects design. There are 3 ...
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12 views

Partitioning variance from logistic regression

Short version How can I partition the variance from the different levels in a nested mixed-effects logistic regression? Preferably using R, but even general principles would be helpful as a start. ...
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19 views

Zero Degrees of Freedom

I'm using a 2-way ANOVA and I keep getting a zero df for the interaction of two of my independent variables. What could be causing this?
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1answer
27 views

compare models using anova in r

I got the following outcome. I am confused with the interpretation. When I consider RSS then model 2 is better than model 1. What does that high p value mean? Does in influence my conclusion?? ...
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7 views

2 birth groups 3 age groups and one variable, what test to use?

I am doing a project on low birth weight cohort and normal birth weight tested at 3 different age groups on one cognitive test. Is this considered a 2x3 ANOVA if I want to know birth group ...
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17 views

Significant box's test equality covariance matrices, How bad it is?

Having equal number of cases across two groups (60 total cases), if one wants to perform a split-plot Anova and finds out that the Box's Test of Equality of Covariance Metrices is less than 0.001 then ...
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1answer
27 views

model compare by anova test

I did model test of in anova. once mod1 vs mod2 , other mod2 vs mod1. Does it matter? CAn I compare two models of different df and different parameters? ...
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16 views

Testing contrast between low/high and high/low

I'm trying to understand the results published in Sagristano, Trope, and Liberman (2002). Specifically, I don't understand what analysis produced the result highlighted in the screenshot below. The ...
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1answer
21 views

How to analyse data when it comes from different conditions

In my experiment, I am varying 4 different parameters (side, eccentricity, latency and ...
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11 views

non significance with one-way ANOVA, but significance with multiple comparisons [duplicate]

I'm comparing deviation between three directions (vrt, lng and lat). I applied ...
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1answer
9 views

Does the mean and standard deviation need to be reported when writing up the simple effects analysis of a ANOVA interaction?

I'm currently carrying out a four-way mixed factorial ANOVA and in the process of writing up the results. I've done simple effects analysis on all the significant interactions between the factors, ...
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25 views

Alpha correction for two-way ANOVA (and post-hoc) with unequal variance?

I have a multifactorial design (3 treatments x 6 time points, n = 6). One sample per subject. Because my sample size is small, I've used the KS test for normality - all groups pass. Still, I'm not ...
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10 views

Homogeneity of Variance, 2 Way Completely Crossed Design

I am looking for some advice as to how I might handle having an unfavorable Levene's test outcome, that is to say a highly significant value. DOE Various containers with water were microwaved for ...
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16 views

Repeated Measures Anova in R

If I have multiple entries for a certain subject-treatment combination, will the aov() function correctly handle these entries when running a repeated measures ANOVA? For example, suppose the table ...
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8 views

Randomized block design for repeated trials

Suppose I measure reaction time of 4 students, initially before any treatment, then after treatment 1, and finally after treatment 2. (Note all treatments will eventually be applied to all students.) ...
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8 views

Significant difference real or due to the internal variability?

In my data I have 9 different sets of data for 2 different groups. Each one of these datasets is the same measurement changing over the time. If I make a graph, I can see 9 lines for each group. I did ...
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12 views

Within Subject ANOVA?

I want to study effect of three factors (Size, Stress and distortion) on readability of graphs. Each factor has two level of difficulties such as easy and hard. Every time I will fix two factors and ...
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20 views

Does the principle of marginality apply to analysis of deviance? [closed]

Just a bit confused, a second opinion would be appreciated.
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11 views

Controlling for Type 1 Errors: Post-hoc testing on more than 1 ANOVA

I have conducted several repeated-measures ANOVA's with post-hoc testing via Tukey's HSD whenever the omnibus F-test was significant. I'm having some confusion about controlling for type 1 errors when ...
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48 views

NEED ANOVA HELP ASAP!

I have been looking at my stats results for 4 days now and I cannot figure out how to interpret the results. I conducted a within subjects experiment in which participants rated 4 neutral symbols on ...
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16 views

Multiple comparison in the unequal variance case

I have found procedures such as Tamhanes T2, Dunnets T3 and the Games & Howell procedure that deal with unequal variances in the one-way model. However, I have a Randomized complete block design, ...
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76 views

Multiple measurements per trial in R

Suppose I wish to assess reaction time of individuals before and after treatment, using R code. Now to analyse the results if I had additional treatments, I could use repeated measurements ANOVA in ...
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18 views

Statistics for catch of tuna longline

I have study on catch for tuna longline. In here I have 3 independent variables (number of hooks, length of branch line & baits) and 3 dependent variables (catch of tuna, catch of marlin & ...
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28 views

Interaction term is insignificant but the interaction plot shows signs of signficance

So, I ran an ANOVA on a dataset which contains over 4500 data points. Without getting into too much detail, I was wondering if there is a simple explanation to this: The p-value for my interaction ...
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29 views

Progression between two exams under three conditions

I want to test if three types of learning mehods have different effects on the progression between two exams. The data was collected like this: A first exam was done with all participants. They had ...
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10 views

MANOVA, when independent variable is not multi-level and P value significance variance [duplicate]

My research has 4 independent variables and 4 dependent variables. My hypotheses are constructed in such a way that 1 independent variable's effect size is checked on 4 dependent variables. My ...
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1answer
30 views

Using Univariate ANOVA with non-normally distributed data

If my data are non-normally distributed and I'm conducting a 2x2 ANOVA, what can I do to correct for this problem so I can report the main effect and interaction output appropriately? Only one ...
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1answer
45 views

Alternatives to one-way ANOVA for heteroskedastic data

I have data from 3 groups of algae biomass ($A$, $B$, $C$) which contain unequal sample sizes ($n_A=15$, $n_B=13$, $n_C=12$) and I would like compare if these groups are from the same population. ...
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50 views

Treating numeric as categorical variable in regression

I need a little bit of help and confirmation that I have the right idea. I have some fake data of 8 tribes; within each tribe members work hard to gain food for their own tribe. No one can speak to ...
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2answers
27 views

T test with one group

I think it is a simple question, but I got many different results and now I am not sure which test to use. I have one group and 2 different scores (higher scores means higher either positive or ...
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19 views

how can i use regression model selection technique and to carryout ANOVA for calculated data [duplicate]

how can i use regression model selection technique and to carryout ANOVA for calculated data I have problem regarding to know , what kind of relationship is excised between parameters to produce a ...
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19 views

Chi-square in ANOVA

I am comparing models that I created with the lmer function from the lme4 package using ANOVA. Paricipants and verbs are my random factors, and RT are the Reaction Times that I measured. From the ...
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37 views

MANOVA, when independent variable is not multi-level and P value significant in MANOVA but not in ANOVA

My research has 4 independent variables and 5 dependent variables. My hypotheses are constructed in such a way that 1 independent variable's effect size is checked on 5 dependent variables. MANOVA is ...
2
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1answer
62 views

Analysis of variance with Weibull or Gamma distributions

I have been trying to find a method to analyse variance on Weibull and/or Gamma distributions but a Google search for anovar Weibull "gamma distribution" yields ...
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30 views

repeated measures ANOVA with covariate

I conducted a repeated measures ANOVA and added a continuous covariate. Now there is a significant main effect of that continuous covariate. If I report that main effect I need to say something about ...