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Questions tagged [anova]

ANOVA is an acronym for "analysis of variance". It is a widely used statistical technique to analyze the source of variance within a data set.

Overview

Although ANOVA stands for ANalysis Of VAriance, it is about comparing means of data from different groups. It is part of the general linear model which also includes linear regression and ANCOVA. In matrix algebra form, all three are:

Y=XB+e

Where Y is a vector of values for the dependent variable (these must be numeric), X is a matrix of values for the independent variables and e is error.

Tag usage

  • SO questions on ANOVA should be about implementation and programming problems, not about the statistical or theoretical properties of the technique.

  • Consider whether your question might be better suited to CrossValidated, the StackExchange site for statistics, machine learning and data analysis.

In scientific software for statistical computing and graphics, function aov implements ANOVA. Note that function anova does something else. See When should I use aov() and when anova()?

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How to do ANOVA for regression models in R?

When I run ANOVA for the regression models which I develop, this error appears: Error in anova.nls(model3) : nova is only defined for sequences of "nls" objects What is the meaning of this error? It should be mentioned that when I run summary of…
user3713988
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SAS: build linear regression model

I need to do build a simple regression model around the productivity of various land units in SAS but I am fairly new to it. I have the following parameters: Prodbanana / ELEVATION / SLOPE / SOILTYPE The productivity vaules of banana are in kg/ha;…
Dallasbarr
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How to make simple ANOVA in R

I have to make ANOVA in R using build-in packages, my data seems like this : dane=cbind(a=rnorm(10),b=rnorm(10),c=c(1,1,1,1,2,2,2,2,2,2)) a and b are variables for which I want to test hypothesis about equality of means in groups assigned by c…
Qbik
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Searching for aov effect tables with minimum values in R

After doing Analysis of variance and and building effects table, I need to capture only 5 of those term's table with minimum values. Because of a long list of factors; as there are around 100 factors starting from x1 to x100, I am unable to…
Shahzad
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How can I test this (interaction) pattern

Hi, I have some troubles understanding which analysis is suitable to test this expected pattern. The idea here is that in Condition 1, the difference between A and B is higher, but small between C and IC. In Condition 2, the difference between C…
rbeginner
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Is repeated anova what i am looking for?

I'm studying the NDVI (normalized vegetation index) behaviour of some soils and cultivars. My database has 33 days of acquisition, 17 kind of soils and 4 different cultivars. I have built it in two different ways, that you can see attached. I am…
Marco Prandi
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Making a histogram

this sounds pretty basic but every time I try to make a histogram, my code is saying x needs to be numeric. I've been looking everywhere but can't find one relating to my problem. I have data with 240 obs with 5 variables. Nipper length Number of…
Jay
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Levene Test on an Anova: "Error in y - meds[group] : non-conformable arrays"

I am having trouble running a Levene Test on an Anova. I keep getting the following error: 'Error in y - meds[group] : non-conformable arrays' Here is what I have: MiniP$Education <- as.factor(MiniP$US_DEGR) MiniP$Sex <-…
ksnider
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table data rearrange in R

I am new to learning R. I have data set like this which is needed to be arranged to perform one way ANOVA. Group Salary B 1000 A 2000 B 3000 A 4000 this needed to rearrange in to Group A Group B 2000 …
user3003900
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How to test if every column is significantly different than the others

I have data.frame in R containing hundreds of columns. I need to check if every column is significantly different from all other columns. I was looking at aov() function, but I don't know how I should specify the model and how to do it for every…
Tilia
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R aov Function - adjusting the alpha value..?

I have always used the aov() function however Im wondering if there is a way or another function that allows the user to define the alpha value..?# I'm assuming these tend to be the industry standard of 0.05....what if I wanted my aov function to…
PaulBeales
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Selecting the highest F value from a looped anova in R

As a part of a project I need to perform anova analysis between the various columns of a csv file. Is there any way I can write a loop to do the anova between the all the columns instead of doing it individually? Right now I am using the following…
Data noobie
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one way anova for multiple classes either matlab or python

i have 4 classes of size (72,22,22) and i want to do anova1 for each pair of the (22,22) in those classes . for example; i wanna grab, let's say, pair (2,3) in each class and do the anova for each pair in the 4 arrays, so the output would be an…
Abdul
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significant difference tests between independent groups in R

x 6.18 3.76 5.15 4.02 2.52 1.41 3.36 8.67 9.36 y 9.39 13.50 10.80 12.70 14.70 13.40 10.10 4.12 10.30 z 6.35 3.90 5.32 5.08 8.38 5.84 3.96 3.78 b 1.15 2.26 1.47 1.93…
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