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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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Is it possible to pass a for loop in a function?

I know it sounds ridiculous but I have to pass a for loop into a function. I have a dataframe with 75+ columns and most of them are categorical variables. One of the variable is called SalePrice and i wish to find the correlation between the…
Aaron
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How can I make two key columns from the different part of the column names in R?

I am going to do repeated measures ANOVA on my data, but to this point, my data is wide. Two independent (categorical) variables are spread across single responsive variable. See the image: https://i.stack.imgur.com/0trSM.jpg I want to create two…
irakli
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Performing T-Test on Time Series

My boss asked me to perform a T-Test to test the significance for a certain metric we use called conversion rate. I have collected 18 months worth of data for this metric dating April 1, 2017 - September 30th, 2018. He initially told me to collect…
Keith
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R: p-value for each row from anova & lm()

I'm trying to conduct an anova for each row and then extract the p-values for plotting. As a reference, I'm trying to adapt code from this post: R, extracting p-value for each row from t.test Here is my snippet: > anova.007.mRNA<-x007 %>% +…
Oars
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Format data to run ANOVA in R

I am trying to run a 3-way ANOVA in R, but my values for each variable are in one column and not separated by rows. Currently, my data frame looks something like this: Season Site Location Replicate Lengths Jan_16 MI Adj 1.00 …
Sarah Cole
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NaNs produced in r

this is my data > longnacl essays Ionic_Strength Water_Absorbancy 1 NaCl1 0.01 52.70 2 NaCl2 0.01 52.02 3 NaCl3 0.01 52.98 4 NaCl1 0.02 43.90 5 NaCl2 …
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Statistic analysis of two groups

i need to analyze this data. Tried with anova and independent t-test but i have no results. i appreciate your comments Group Biomass 1 3876 3876 3875 2 4016 4016 4016 Values represent area as growth
Biologist24
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multifactor anova keeps giving error codes

I am working with a dataset in which I need to compare ordinal data to continuous data in a different column. i.e, individals were categorized (by age, actually) and I need to compare different age ranges to two different test values. I have been…
CMRoan
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Did I just do an ANCOVA or MANOVA?

I’m trying to do an ANCOVA here ... I want to analyze the effect of EROSION FORCE and ZONATION on all the species (listed with small letters) in each POOL.STEP (ranging from 1-12/1-4), while controlling for the effect of FISH. I’m not sure if I’m…
metazoa
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F-score and standardized Beta for heteroscedasticity-corrected covariance matrix (hccm) in R

I have multiple regression models which failed Breusch-Pagan tests, and so I've recalculated the variance using a heteroscedasticity-corrected covariance matrix, like this: coeftest(lm.model,vcov=hccm(lm.model)). coeftest() is from the lmtest…
Calen
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How can I estimate variable influence of the factors in my model rather than just factor levels?

I created a regression model And i want to estimate an influence analysis for each factor. Meaning take the square Wald-estimation (z-value) for a specific factor and divide it by sum of squares of their Wald-estimation. and that how I estimate the…
Dima Ha
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Extract the ANOVA table to Excel/.csv

I'm wondering if it's possible to extract the table that results when running ANOVA to an Excel or .csv file. I'm running a repeated measures two-way ANOVAs with RMAOV2 (http://uk.mathworks.com/matlabcentral/fileexchange/5578-rmaov2). Here is the…
dede
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Overall ANOVA for Linear Models in R

I can use the anova function to get the ANOVA table for linear model. However this gives the individual effects of each explanatory variable on the response variable. I wonder if there is any function in R to get the overall ANOVA where we can get…
MYaseen208
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Inference() Function Insisting That I Use ANOVA Versus Two-Sided Hypothesis Test; R/RStudio

I'm trying to use a custom function called Inference() as seen in the code below. There's no documentation for the function, but it is from my DASI class in Coursera. According to the feedback I have received, I am using the function properly. I'm…
Jason T. Eyerly
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ANOVA and sample group associated to a variable

I have a variable X and and 16 groups of samples. I would like to know which group is the most associated to this variable (the one with the lowest values actually). I performed an ANOVA and a TukeyHSD/post-hoc but that only highlight which groups…
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