Questions tagged [anova]

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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Geometric interpretation of the differences between the mean (ANOVA)

First of all, a disclosure: I'm a medical doctor trying to understand statistics for research. Coming from a non-mathematical background I can do many mistakes. I've read some traditional books of ...
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On the specific difference between RM ANOVA and paired sample t-test

Paired sample t-test and Repeated Measures ANOVA with a dichotomous predictor are two tests that answer the same question, and output the same p-value as far as I can tell. This question has been ...
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Bland-Altman analysis for repeated measure across time with one method of measurement

Just like to seek some clarification. As far as I understand and have read "The Bland–Altman method calculates the mean difference between two methods of measurement (the ‘bias’), and 95% limits of ...
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ANOVA testing for User Activity on a website

Problem: I am trying to determine whether visitors on a web-site are more likely to perform a certain action (click a specific button in this case) if they view a specific section on the website. I ...
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Is it possible to have ANOVA-type assesment of main efects in quantile mixed linear regression?

As in the title. I would like to assess the main effects by applying a joint test to the quantile regression. In R it's done by lqmm(), but neither anova, Anova, emmeans, or multcomp support it. I ...
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Coefficients table and in the ANOVA table

Questions: What is the conceptual difference between the test of the predictor's effect in the coefficients table and in the ANOVA table? My attempt: The overall significance of the model is ...
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Are normally distributed sample means equivalent to normally distributed residuals?

According to t-test:Assumptions "The means of the two populations being compared should follow normal distribution" The one way ANOVA test in case of 2 groups equals the t-test but the ANOVA ...
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Compare p values of ANOVA and $\chi^2$ test

I have dataset with different types of features (numeric/continuous and binary). Altogether 66 features. I want to find a small subset of features that is sufficient for a multi class classification ...
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Why am I seeing 0 degrees of freedom when testing main effects using lme4, but see 1 df when testing interaction?

So sorry if this is a dumb question, but I've been searching around and can't figure out what's going on. I'm running a mixed effect model with 2 fixed effects and random intercepts, as shown below. ...
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How to statistically analyze data from an observational study (and relate it to a questionnaire)?

I'm going to be doing a study for a psych class which will involve observing how frequently a certain amenity is used in different setting conditions, such as having an informational sign (I will be ...
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Global test of the hypothesis, and ANOVA

I am trying to analyze the following results for the house selling price data. My questions are: a. How can I interpret the results of the global test of the hypothesis that none of the explanatory ...
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How to analyse this pre-test and post-test double-blinded RCT study?

I have conducted a study where participants are split between two groups (treatment and control). I want to measure changes in depression and sleep disturbance pre and post-test (before and after ...
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For the house selling price data, interpretation of the ANOVA and lm

I am trying to analyze the following results. My questions are: a. How can I interpret the results of the global test of the hypothesis that none of the explanatory variables has an effect? b. ...
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Bonferroni correction in one-way ANOVA for one dependent variable

I have a quick question I hope somebody could help me with; If I have two one-way ANOVA's in my research just comparing the means of three age groups for a single dependent variable (so two seperate ...
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Is the dunnett test implemented in python? [closed]

I would like to perform a dunnett test after an ANOVA in python. I found the dunnett test in langage R but not in python. Does a library exist in python too?
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What Statistical Analysis test do I run for Pre/post test?

Hello I am conducting a study where I examine patients who have not received a flu vaccination. In all I have 45 participants all who have not received the vaccine. I implemented and educational ...
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ANOVA with tree species type [closed]

I'm performing ANOVA on some forest data and one of the categories is non-numerical. A comparison is being made between elevation, and main tree species. There are only two possible species, entered ...
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Conducting Statistical Analysis on Evolving Populations

I am writing a paper on the evolution of altruism. To do so, I have written a computer program that simulates the environment and allows a population to evolve. Organisms are either altruists or are ...
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prepare data for Repeated Measure Anova

I'm very confused about how to deal with repeated measures. I have 3 groups of participants, each of them exposed to 3 conditions (A,B,C) and each condition is repeated 5 times. Basically like this: <...
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How to use filter-based feature selection for mixed data types?

The idea behind filter-based methods of feature selection is that we assign a value to each feature, where the value indicates how important the feature is for predicting the outcome variable. We can ...
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Finding Mutually Orthogonal Contrasts

We're given that Contrast 1 is $ ψ_1 = τ_1 - τ_2$ $ ψ_2 = τ_1 + τ_2 - τ_3 - τ_4$ We're suppose to find contrast $ ψ_3 $ such that its mutually orthogonal to $ψ_1$ & $ψ_2 $ given that our ...
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The response time in milliseconds was determined for three types of circuits. Experimental Designs

The response time in milliseconds was determined for three different types of circuits that could be used in an automatic valve shutoff mechanism. The results from a completely randomized experiment ...
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Non-parametric ANOVA with non-homogenous variances

I need to know if a continuous dependent variable Y differs between two groups X1 and X2, controlling for a confound variable Z (that is continuous and highly correlated with Y (Spearman's rho ~ 0.7))....
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RMAnova or ANCOVA

I have read many similar questions but I could not find a post completely fit to my experiment design. I have two systems: A system and B system. Participants of Group A use A system to conduct two ...
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ANOVA on time series with correlated residuals

Let's say I have $K$ groups for which I want to do ANOVA and the residuals perhaps are correlated serially but in particular the residuals of two different groups are correlated. This should not be a ...
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One sided hypothesis for ANOVA approach in SLR

In Simple Linear Regression, to test the hypothesis $H_{0} : \beta_{1} = 0$ in ANOVA approach (using F test), is it possible to define one sided alternative hypothesis, such as $H_{1} : \beta_{1} > ...
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Sample Size for ANOVA with moderation [closed]

How do I calculate the minimal sample size for a one factor between subject experiment if I want to include a moderator?
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anova from R: output and interpretation of F-Tests

These question have been asked in many different ways as you can see here or here; however much of this topic is still beyond my understanding. Let us consider a model having response variable $Y$, ...
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Repeated Measure ANOVA, GLM,GEE, Linear mixed model, Generalized linear mixed model?

I have a table like below (it is a small subset of my data. In this table, I measured one variable over 4 different time points (T1,..., T4), now I would like to check is there any significant ...
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Does it make sense to use ANOVA with one-hot-encoded data?

I have a data set with different feature types (numerical and categorical). I applied one-hot-encoding to the categorical features and then used ANOVA to find most relevant features. 6 of 66 features ...
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Repeated measures anova p-value not improving with larger sample size

CONTEXT: I have an experiment of 2 groups of 20 individuals each (40 people total). The test group received an intervention to aid them in converting leads and the control group did not. GOAL: I'm ...
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What is the difference between the Pseudo F Index and the F Statistic?

I'm wondering what the difference between the Pseudo F Index and the F Statistic is. The Pseudo F Index is used in clustering analysis as an index to determine the the right number of clusters in a ...
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How to compare 2 groups (control + patient) to show significant differences?

I am conducting an experimental study. I have 2 groups: The first group contains 3 healthy persons and the other one contains 3 patients (sick people). For each person of the sudy, we collect several ...
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Calculating heritability from half-sib design

I'm trying to measure heritability of a trait, flowering time (FT), for a set of data collected from a half-sib design. The data includes FT for each mother plant and 2 half siblings from that mother ...
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Convert repeated-measures ANOVA into linear mixed-effects model

I am a beginner to R and it is my first time asking a question here, so thanks in advance for your patience. I would like to convert a repeated-measures ANOVA that I run into SPSS to a linear mixed-...
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What is the best method to determine statistical differences between percentages that do NOT satisfy ANOVA assumptions?

I am working a project where I analyzed image classification accuracy percentages for three algorithms. I laid out 36 plots in an agricultural field and took aerial images over a period of 5 (non-...
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How to approach unbalanced data with unequal sample sizes for comparing means

I have a data with a continuous and two categorical (population and sex) variables. I want to test whether the means among the groups are significantly different. However, this is not an experimental ...
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Checking ANOVA for unbalanced data

I would like to figure out if there are significant differences between the following groups. I use R: ...
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ANCOVA: Measured weight of 5 participants 5 times on 3 different weight scales. Should I use participant ID as a covariate?

I measured weight of 5 participants, 5 times each, on 3 different scales accurate to 5 places after decimals. In total, I took: [5 participants] x [5 times each] x [3 different scales] = 75 ...
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Comparing means of a subgroup 1 from group B and subgroup 3 from group A

I have encountered a problem while analyzing ANOVA in SPSS. So say there are 5 schools, and each school is divided into 3 treatment groups. Analysis already showed that, overall, school B scored ...
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How can I group my factors for post-hoc test in Minitab?

I've recently been using R for my data analysis, but was struggling so I've turned to Minitab for the first time. The data I'm using can be seen here - Is it possible to do a post-hoc test on a ...
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Fish size test among months location

Which is appropriate test to find if there is significant different of fish size collected among months and/or locations? Any help to provide correct r code? aov(TL~month, location) Or lm(TL~month, ...
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Machine Learning: 1-way ANOVA from data collected where all samples are not independent?

I am analyzing machine learning imagery classification by using 3 different algorithms to classify imagery and a sample of ground-truth points to collect an overall classification accuracy. I wish to ...
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Statistical analysis of amino acid profiles, quantitative vs qualitative methods?

I work on a study comparing the amino acid profile of 5 sample groups with 3 replicates in each group. This is how the data looks like except that there are 17 columns (one for each amino acid) in ...
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How to plot the results of a Kruskal-Wallis or a Welch's ANOVA?

Let's assume that I have two datasets for which I have measured three continuous variables. In both datasets, these variables have been measured on three groups of observations and these groups only ...
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ANOVA/ANCOVA - how to analyse

In a basic research design where you want to test how some intervention (let's say our IV is 'drinking' with the categories water; sprite; and rum) affects some continuous measurement (let's say ...
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How to interpret sppbi function of the WRS2 package?

I'm hoping to receive some help in interpreting the output from the sppbi function as part of the WRS2 package. I've read the paper by Mair and Wilcox (2019) titled Robust statistical methods using ...
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Split plot with RBCD in R: Are inferences valid when output reports some effects are not estimable?

Data are from an agricultural experiment and are the proportion of turnips damaged by cabbage maggot in different insecticide treatments (note preliminary investigation suggested data were ...
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Statistical testing for before and after treatment of two independent groups?

I have two sets of continuous variables, weekly sales per customer. One set contains the sales of customers in the control group, and the other set contains the sales of customers in the test group. ...
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When do I have to use orthogonal contrasts instead of non-orthogonal ones?

This is the same question as asked here, but of course I think with a different twist. A definition of orthogonal contrasts is given in another (great) answer to a popular question on Cross Validated ...

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