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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Repeat measures regress

I have a question about using regression for repeat measures analysis. I have a design in which each participant viewed 4 sets of pictures. 2 sets were positive and 2 were negative. There were 2 ...
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19 views

Repeated measures or two-way ANOVA, and power analysis

A sample of patients will undergo two treatments. Every patient will receive both treatments.One treatment will on the left side and the other different treatment on the right side. Repeated ...
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17 views

Scaling data constrained to be varying between a floor and ceiling set of values

I have data that range continuously between the values of 0 and 2, usually somewhere in between close to 1 on average. 0 is a "floor" and 2 is a "ceiling." The data describe more than one group of ...
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2answers
29 views

Minimum sample size for 1 way ANOVA?

I have tested a group of participants over various time points and I want to investigate whether mean score on each subsequent time point is significantly different to the mean score at baseline (eg. ...
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1answer
15 views

Normality requirements across tests

I would like to understand the reason why normality is required in many tests. T-tests: I read that what needs to be normal is the sampling distribution rather than the sample distribution. But since ...
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42 views

Correcting data for mean but also variance

My data: I have data that range from 0 to 2 for numerous individuals. The scores are more or less normally distributed and vary continuously, but the scores are always between 0 at the minimum and 2 ...
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25 views

Reject or Accept the Hypothesis [on hold]

Simply . I am confuse that how can I know that I may reject or accept the H. ? what would be the most significant value ?
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1answer
19 views

What statistical test to use to examine attitude and which components have strong/weak influnces on attitude? 4-point Likert Scale survey

This is a quantitative study using survey to examine attitude towards online reading. In the survey, there are 5 main components which contribute to overall attitude. Each component has different ...
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1answer
18 views

Different means with non-significant anova

I did an ANOVA test summary(aov(m$Y~m$type)) and I get a p-value of 0.067 i.e. the means are equal. But my means by type are these ...
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30 views

How can MANOVA report a significant difference when none of the univariate ANOVAs reaches significance?

I would just like to ask if it is normal for the values from my multivariate tests to be significant but for the values from my univariate tests of between-subjects effects table to be insignificant. ...
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2answers
32 views

What test to compare three groups with data before and after an intervention?

I am writing a proposal for a study. I have 3 groups: Group A- receiving specialized intervention technique Group B- receiving regular intervention Group C- control/receiving no intervention I ...
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15 views

Interpreting a repeated-measures two-way ANOVA in R

I'm not sure if I've structured the model correctly, and if I have, I'm struggling to interpret the output I get anyway. I had 40 respondents exposed to 4 groups of stimuli - let's call the groups a, ...
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11 views

Genetic algorithm for factor selection

I'm planning to implement analysis of variance for different levels of factors, the problem is that I have 20 independent factors. Of course, the best model should include only significant factors. Is ...
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11 views

One way ANOVA: post-hoc comparison “adding letters to graph” [migrated]

I am working on a project for one of my classes and cannot figure out how to obtain the letters for treatment comparisons after using the tukeyHSD post-hoc test. Is there a simple way to do this? ...
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33 views

anova vs. multiple regression

I am interested in the effects of A, B, and their interaction (AXB) on Y. The effect of A is not significant while I am using ANOVA, but it is significant while I am using multiple regression. ...
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1answer
24 views

Relate $Var(y)$ with $Var(y)_{(i)}$

How can I relate $Var(y)$ with $Var(y)_{(i)}$ where $Var(y)_{(i)}$ is de variance of the data with the ith item removed. It is necesary first relate $\bar{y}$ with $\bar{y}_{(i)}$ and it complicates ...
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12 views

Control group in Incomplete Factorial Design

here, in title of Incomplete Factorial Design, it is written that " it is actually impossible to implement a group that simultaneously has several levels of treatment factors and receives no ...
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28 views

$3^3$ factorial design

Suppose in a $3^3$ factorial design, factor A has three levels. We want to test the significance of A and after setting hypothesis $$H_0:\alpha_i=0 \quad\text{for}\quad i=1,2,3 \quad\text{Vs.}\quad ...
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10 views

Which statistical test should I use for my questionnaire on Body Image? [duplicate]

I am doing a study on body image and how that differs for people depending on their age, race/ethnicity, and socioeconomic status. Should I be using a 2-way ANOVA test (between subjects) I will be ...
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25 views

basic study question

I am measuring heart rate variability in 20 patients and then 20 controls at baseline and then after an intervention. What kind of statistics would be used to compare the intervention group to ...
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1answer
60 views

Multiple regression or anova or bestglm or forestplot or Boruta

I have data on a continuous health variable and following others: age, gender, height, weight, waist, city and season. I applied multiple regression and got following output: (age, gender, height, ...
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2answers
63 views

How to determine whether a variable is significant using Pr (>Chi) and Df?

I wonder how can I determine whether a variable is significant using Pr (>Chi) and Df? Take following ANOVA table as an example, I know variable type is ...
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2answers
24 views
6
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1answer
40 views

How to tell that a reciprocal relationship exists by a residual plot?

I'm following an example from the book "R by Example", where they talk about two-way ANOVA. The database used in poison. The analysis is: ...
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28 views

How can I write the t-statistic in cases where I have three populations and linear relationship between the three?

I sample height measurements from people from three populations, which I call P1, P2, and P3. My null hypothesis that the average height in group P1 equals 2/3 times the group P2 average plus 1/3 ...
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1answer
14 views

Test equality of binomial variances across four groups

I have four 100x1 vectors of binary outcomes of a particular experiment. I want to test for equality in variance across all of the four different treatment groups. At the moment I have used the ...
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15 views

Interaction in ANOVA and post-hoc tests

I have the following questions: 1) Is it correct that I'm only allowed to do post-hoc tests as long as the results from my ANOVA reach significance in the interaction? 2) When I have the ...
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1answer
50 views

Getting a meaningful metric for variation in this type of cyclical, panel data? WSS won't exactly cut it!

This is related to a previous question I have asked, but I am not after visualization but rather a meaningful summary statistic. Situation: I have many (150k) customers. Each generates his own ...
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2answers
52 views

Can someone explain what it means for an observation, from a group of data, to be independently and identically distributed?

I don't quite understand what the difference is between an observation being independent and it also being identically distributed. Can someone explain please?
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1answer
39 views

Scientifically reasonable or not ? exclusion of very, very uncertain values from statistical analysis

I have 5 treatments A1 .. A5 and 4 independent individuals per treatment, whose parameter X is of interest to me. My objective is to compare X among treatments, and see if one or more treatment ...
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16 views

3-way repeated mesures ANOVA

I conducted reaction-time experiment with three factors - set size (4, 16, 64), presense of the target (present, absent) and the third factor with two levels (C, F). After that I ran a repeated ...
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1answer
23 views

Contingency Table from ANOVA?

I am needing clarification on something that I thought I read was possible and is stuck in my head needing answered as I am not following how to do it or I just missing a key concept. I am not a ...
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19 views

What analysis should I run?

For an RCT, I want to test scores on BES(Binge Eating Scale) and BMI over time for two different groups(experimental and control group)to register whether treatment had an effect on reducing symptoms ...
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1answer
14 views

Repeated Measures - repeat measures at same site but at different distances

I have a study where I have two stress zones (high and low stress). In each zone, I have 10 sites. Within each site, I am setting up traps at 1m, 2m, 3m, 4m, and 5m away from a focal plant. My ...
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1answer
16 views

Can I justify using a one-tailed test in for this interaction effect?

I have an experimental setup with 2 factors, site and disturbance treatment. I have reason to suspect that plots at site A will be more affected by treatment than plots at site B. My response ...
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1answer
31 views

Perform two-way ANOVA (one observation per mean) in R?

How do we do two-way ANOVA (one observation per mean), as testing H_A in Section 8.5 in Seber and Lee's Linear Regression Analysis, in R? Note that the linear model for this case doesn't have ...
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8 views

Split-plot or factorial anova?

Sorry about the total noob question, but I'm not sure if i'm using the correct analysis. I have two groups (a condition and a treatment), and these subjects have to respond to two different colours as ...
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1answer
36 views

Two-Way ANOVA calculation using summary data (mean, SD, sample size)

I want to perform a two-way ANOVA using the groups' means, standard deviations, and sizes. There is this website but just for one-way ANOVA. Also there are R packages and other programs that can do ...
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42 views

When an effect size has to be considered sufficiently large?

I submitted a paper in which I analyzed the data by a mixed design ANOVA. I reported generalized eta squared as effect size. After significant interactions, I conducted planned comparisons. A reviewer ...
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47 views

ANOVA using count data

I'd like to perform a two-way ANOVA on count data. I was told to first fit a GLM and then do the ANOVA. My first problem is that ...
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2answers
16 views

Significant F in ANOVA

What does a significant F statistic in ANOVA mean about the differences among the three or more groups means being compared in the test
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1answer
15 views

Wrong error term for test of random factor in two-way mixed-effects ANOVA in SPSS

In SPSS, when I run a two-way mixed-effects ANOVA (with factor A fixed and factor B random), the between subjects effects table reported by SPSS uses mean square for the interaction (MS_AB) as the ...
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For an ANOVA comparing here treatment condition

a) None of these choices is correct. b) All three of the population means are different from each other. c) At least one of the three population means is different from another mean. d) There are no ...
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57 views

How to evaluate similarity of datasets based on summary data?

I have summary data that I want to compare to my own data. For the summary data I do not have access to the underlying data, however, I know the percentiles as shown below (A). I also calculated ...
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Is analysis of variance here a correct test?

Suppose I have measurements: $f(x_i, y_i)$ $f(v_i, w_i)$ $f(x_i, v_i)$ $f(y_i, w_i)$ If I put these into groups $(xy), (vw)$ and $(xv, yw)$ and do a single-factor ANOVA with the previous three ...
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27 views

T-test or ANOVA

I have 4 groups. I would like to compare the effect of 3 different treatments relating to drug treatment of a sample individually against a single control sample. Control (no drug) Treatment A (low ...
3
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38 views

Need Help w/ Research Proposal

I am currently doing a master's research proposal (experiment hasn't been completed yet) and need to decide what statistical test to use. My research question is observing increases in bowling ...
4
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1answer
21 views

Tests of equal variances- am I doing this right?

In my experiment, i want to test whether dogs are more likely to head directly to a goal. The data is in the form so that 0(degrees) is a heading to the goal, -90deg is a heading to the left and 90deg ...
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21 views

Using mean for Regression vs Raw data for anova?

I would like to learn what is the correct way to approach analysis of this data: I have 5 grasslands, and in each grassland I have 30 spiders. For each spider I have an estimate of what proportion of ...
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Assessing variability in a multiilevel model

This looks like a classical problem, but I couldn't find an answer, maybe because I use wrong keywords in my search. Let's assume you are tracking company monthly revenue values over a couple of ...