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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Unequal sample size one way ANOVA

I want to compare the means of X between BMI groups, but have unequal sample sizes between my groups. ...
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9 views

Determine if one-point samples are significantly different from a set-of-values sample

Well, I have a sample x made up of 28 cases, sample y -> one case, sample z -> one case. I would like to determine if y and/or z are significantly different from x. It's not possible to take more ...
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29 views

What statistics should I use for my comparison?

I am currently analyzing leaf senescence over two sites, using 6 species, each with 5 replicates. The senescence is measured in percentages. How could I analyse the two, to see if there were any ...
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17 views

How to do power analysis for two-way analysis of variance? [on hold]

The pwr library can be used to do power analyses when testing with 1-way analysis of variance. Are there similar libraries for 2-way ANOVAs? How could I got about doing this in R?
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38 views

Dissertation-results section

basically i am testing 2 species of pigs, 2 pigs of the same species in one enclosure and another 2 in a different enclosure, My aim is to see if alterations to feeding regimes have an effect on an ...
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10 views

How to test for interactions of continuous measure with two repeated-measures factors in R?

I am doing an items analysis of difficulty ratings of a large set of math problems which were constructed to represent the factorial combinations of two binary factors, feature1 and feature2. The ...
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10 views

Performing t test, one-way ANOVA from mean and SD using SPSS

I have the following summarized data: Group 1: n=44, mean 12.1, SD 2.0 Group 2: n=56, mean 13.2, SD 2.5 Group 3: n=42, mean 12.7, SD 2.3 Is it possible to perform the t test comparing means of group ...
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39 views

box-cox transformation altered my anova result

Here is a summary of my actual data ...
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45 views

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 ...
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14 views

How can I make an ANCOVA in R (Prior to a Cox ph model)?

I want to make an ANCOVA analysis of the survival rate of flies after being on a bad diet for the first 21 days of their lives compared to those always on a normal diet. I have studied the responses ...
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3answers
36 views

How to test relationship between weight gain and light exposure in crickets

I am a biology major, and will be running a study and am unsure of what statistical test to run. Here is a summary of what we will be doing: We are testing to see if there is a correlation between ...
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10 views

homogeneity of variance two way model sas

How do I test for homogeneity of variance of a two way model in SAS? I am trying to run a two-way anova model.
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27 views

Project help [undergraduate] [R]

I have to do a project for my statistics course, which I have now finished but would very much appreciate some insight and help as I've never done anything like that before. I was given data on ...
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17 views

within group agreement, intra-class correlation, one way ANOVA to justify data aggregation

I am working on my research involving aggregating individual data into group data. Predictor: Task conflict (3-item scale) Process conflict (3-item scale) ...
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8 views

Converting Repeated Measures Code in SAS to Equivalent in R [migrated]

I am attempting to convert existing SAS code I have for a research project into R. I am, unfortunately, finding myself totally clueless on how to approach this for repeated measures ANOVA despite a ...
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11 views

What is going on here? Omnibus repeated measures ANOVA is marginal, but follow-up planned pairs <.05

I have a repeated measure ANOVA with a decent sample size (124 participants, with a score for each person for 3 conditions). The data are moderate to strongly positively skewed, (though similarly). ...
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2 views

Easy ANOVA Setup Fixed vs Random Effects

A researcher wants to compare two methods (M1 vs M2) to teach math. The researcher picks a random sample of 8 students, and assigns at random 4 students to learn under M1, and the other 4 students ...
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1answer
50 views

Size of Tukey's 1 Degree of Freedom Test

In Oehlert (p. 218) the following algorithm for computing Tukey's one degree of freedom test for non-additivity is suggested: Fit a preliminary model; this will usually be an additive model. ...
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23 views

Optimal model/statistical test for my design?

I have a design with 1 between-subject factor and 2 within-subject factors as independent variables and 5 dependent variables (longitudinal accelartion, lateral acc., response time, first conscious ...
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19 views

Pairwise comparisons with covariates

I have a simple ANCOVA model such that outcome ~ sex + group with outcome being continuous, ...
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14 views

How to run ANOVA on multiple groups of samples, each composed by different variables

I have a $m$ x $n$ matrix, where the $n$ columns are split into multiple classes. If I had only a $1$ x $n$ vector, I would have used ANOVA to evaluate if all subset of columns had the same ...
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2answers
28 views

Should I use paired t-tests or ANOVA when comparing multiple variables from 2 tests?

I had 50 subjects perform two 30-minute cycling time trials on separate days. I would like to compare the means of several variables from each of the two tests: Cadence, Heart Rate, Power Output, and ...
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14 views

ANOVA based on mixture of within-subject and between-subject experimental design

I have finished an experiment, and I used a mixture of within subject and between subject design, I am wondering if there is a specific name for this type of experimental design? I would like to find ...
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14 views

How should one incorporate multiple forms of information about a single variable into a model?

I sincerely hope this is a question that can be definitively answered! I'll do my best. Let's say I have two treatments, flower removal and defoliation, that are fully crossed in an experiment, and ...
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11 views

Zero-inflated data? Comparing means in SPSS

I whish to know how to compare means with zero-inflated data. I tried to perform an ANOVA test but obviously comparing means it's impossible since some treatments are very rich in zeros. I'm studying ...
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26 views

Longitudinal pre-post test/follow up

I am an undergrad student trying to get my head around statistical analysis. Can someone help me to make sense of the best way to analyse my data? ANOVA, ANCOVA, t-tests....it is all a foreign ...
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10 views

Anova Post Hoc Test

I am running an anova in SAS on the average hours worked for a country. With those countries grouped into 3 regions. When I run the anova I get a F value of 3.64 and P-value 0.0379. With these ...
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20 views

Repeated measure design

Say I have two groups of people A and B. For both groups, I take repeated measurements of a certain variable C. Now, I would like to say something about the difference between the median value of C ...
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13 views

SPSS ANOVA Can't Find Independent variable (factor)

I want to know if there is significant differences between groups. I have a string variable "Site" which is grouped into 7 (Values 1-"site A"; 2 - "Site B" and so on). The problem is i can't find ...
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how to interpret the two-way ANOVA

I have a data set like below, and I would like to answer the question "whether the mean of v1-v4 by income group differ from each other?" ...
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5 views

Post-hoc test on 3 groups comparison

I have 3 groups each with 6 values. After performing acceptable levene test for Homogeneity of Variance, I performed Anova on my data. It was significant, and I started to perform post-hoc test. The ...
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15 views

ANOVA on unevenly spaced time data

I have a dataset with three treatments (P+, P- and T) and want to test the effect of the treatment on the mortality (continuous variable). Data are unevenly spaced in time. I decided to handel this by ...
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1answer
22 views

Can I perform a chi-squared analysis with a categorical variable and the means of a continuous variable?

I have one variable that is categorical (with 5 levels), and another variable that consists of either mean or sum scores (0 to 28) due to the way you have to calculate the scores of this measure. Can ...
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20 views

Non Probability Analysis

I want to quantify the results of my non-probability survey. Are there any analysis techniques I can use that don't require or assume randomness other than descriptive?
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37 views

Testing differences in slope in time series of repeated measures data

I have a dataset wherein we measured a response in each sample at 20 time points for 3 different treatments (A, B, C). The response for each sample can be reasonably fit with a simple linear ...
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15 views

Unequal Samples in Two Factor Repeated Measures ANOVA Mixed

I am interested in the effect of drug on a cell morphology. Observations on a single cell are made across several domains(let's say 25 different domains), and I am also interested how these changes ...
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23 views

Multiple t tests or an ANOVA?

I have low anxiety and high anxiety participants (21 in high anxiety and 20 In low). I measured anxiety and then categorised Pts according to this. They completed two memory tasks. In one memory ...
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45 views

How to statistically validate a Framework?

I am creating a Framework, that has independent variables A and B. It has dependent variables C, D, E. F, G, as shown in the diagram. Framework I understand that only after validating a Framework we ...
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Can I use experimental data from one experiment in another?

I ran an experiment with a simple 2 x 2 factorial design. Subjects were high school students. Factor 1 = school (school 1, school 2). Factor 2 = group (treatment/control). N = 322, split quite ...
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1answer
45 views

one-way anova, one group has no variance

I have 20 genotypes for comparison (each has n >or= 5), however one group (control) has no variation (each sample = 100%). Can I apply one-way anova in this case. If not, what test would be better. ...
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1answer
39 views

One-way repeated measures ANOVA vs. two-way ANOVA

In a balanced repeated measures one-way ANOVA, we compare the true averages of a response variable across time points. Are the results about the time effects equivalent to those from a classic two-way ...
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25 views

choosing between non-linear/logistic regression models

We are fitting regression models to dose-reponse data obtained from drug assays. Where a drug has an effect on cell viability, there is often a sigmoidal relationship between the proportion of viable ...
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28 views

Analysis for a repeated measures design with covariate that varies over conditions?

I'm trying to find the correct analysis that will allow me to carry out the equivalent of a repeated measures MANCOVA with a covariate that varies over three conditions. Basically I have an experiment ...
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14 views

Question about what analysis to use

Im trying to do the statistical analysis for my thesis, but am unsure of what test to run. I have two groups, each who completed the same task. The task has 4 levels to it and each level provides ...
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38 views

Normality and homogeneity

I have performed certain statistical tests (ANOVA, DMRT, t-test, etc.) assuming my data is normal as well as with homogeneous variance. Now my paper is almost accepted in a reputed journal, reviewer ...
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9 views

Iterative Differential Expression Analysis for Multiple Categories

I have a dataset which consists of one categorical variable and many numerical variables. This is how my data is formatted: ...
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36 views

Departures from normality in factorial design

This paper (http://psycnet.apa.org/journals/med/6/4/147/) states that departures from normality can be tolerated for one-way ANOVA. "The results give strong support for the robustness of the ...
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8 views

Help with 2 way ANOVA Final Equation

I conducted a 2 way ANOVA for resting pulse rate (DV) and gender (IV) and 3 exercise levels (IV). The interaction was not significant and neither was exercise. The main effect gender was significant. ...
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1answer
24 views

Computing the true effect size from F-values and sample sizes?

I'm trying to extract a bunch of effect sizes from a couple of different studies in for which the authors have performed ANOVAs on their data. More specifically, I'm interested in the main effects of ...