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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Is it an ANCOVA?

In a study, baseline pulse is recorded. Participants are asked to watch a funny video and a thrilled video for 10 minutes. Pulse is recorded again. The objective of the study is to investigate ...
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experimental research design

In an experiment, same group of participants are required to test (low and high) visual quality of a user interface. The goal is to find whether perception of usability is affected by any of the low ...
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Experimental Design: Comparing 'Completely Randomised Design' to 'Randomised Complete Block Design'

Suppose I'm designing an experiment, and want to run an ANOVA test to see if there's a difference between my treatments. Suppose there is no variability within our experimental units (or very little), ...
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What to do with non-normality and heterogeneous variances in Two-Way ANOVA when transformations do not work?

I'm conducting a Two-Way ANOVA with my two factors being Sex and Cohort. I have data from two cohorts of subjects, with each cohort consisting of males and females that were measured on one response ...
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Appropriate analysis for three different measures of anxiety pre & post intervention

My study: To examine whether a self-talk intervention has an effect on anxiety. There are two points of measure, pre and post intervention. Anxiety was measured as Somatic anxiety, Cognitive anxiety ...
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8 views

Power Analysis for Within Subject ANOVA

I am going to be collecting survey data that asks for participants' attitudes towards four groups of people. For the sake of this example, let's say that it's black women, black men, white women, and ...
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1answer
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Showing that $\sum_{i=1}^{n}\sum_{j=1}^{n}(a_{i} - a_{j})^2 = 2n \sum_{i=1}^{n}(a_{i} - \bar{a})^2$

I wish to show $\sum_{i=1}^{n}\sum_{j=1}^{n}(a_{i} - a_{j})^2 = 2n \sum_{i=1}^{n}(a_{i} - \bar{a})^2$ for any numbers $a_1, a_2, ..., a_n$. I assume the first step $+\bar{a}$ and $-\bar{a}$ in the ...
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Trying to run ANOVA with time variables

First, can I do this? I never learned of using hours:minutes:seconds as ANOVA values. Second, out of my 3 groups, only one is normal and no transformation will work (can I even use transformation for ...
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Planned contrasts in ezANOVA

I have a data set that is 3 x 5 and I can easily run a repeated measures ANOVA using ezANOVA in R. I now wish to have planned contrasts going into the ANOVA. The data consists of one control ...
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1answer
60 views

Statistical significance in time series (R)

Stats newb here, I have to determine if two time series are really different instead of being part of the same population with noise in the samples. The data is a comparison between two algorithms ...
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1answer
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Repeated measures analysis with participants measured across time and treatment groups

My data consists of people who chose either no treatment or treatment and were given a specific assessment at time 0, 1, 2, 3, 4, 5,... . Participants may miss an assessment but will still be ...
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1answer
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Fundamental question about applying Anova

I have a fundamental question about applying ANOVA. Suppose we are testing 4 drugs which reduce blood pressure. Our experiment contains 4 drugs + 1 Placebo. We give these to 3 types of patients ...
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ANOVA possible?

I have 2 groups (variable = condition) Control, Experimental - I have coded them as 1,2 in SPSS. I have measured these at three time points - pre, ret1 ret2 (currently just a string variable) I have ...
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1answer
11 views

Multiple Comparisons test strategy

I have a test data with 3452 subjects , I have 5 different algorithms that detect the presence or absence of a disease. ...
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2answers
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Appropriate test for comparison of 50+ groups

I am currently working with a data set containing several hundreds of thousands of instances for which I am trying to find the most appropriate analysis. The goal is to determine whether there are ...
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2answers
38 views

Statistical test in R for count data

I am struggling with using the correct test for count data in r. The dataset I have is the number of nymphs produced by three aphid species on wheat. So this is count data with one response variable ...
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1answer
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Checking model assumptions for a one-way ANOVA model with unequal sample sizes

Given an unbalanced completely randomized design with two treatment groups of unequal sizes and an appropriate one-way ANOVA parametric test, how can I properly check the validity of my model ...
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When and when not to use zero values in one-way ANOVA

I have a dataset consisting of 5 pollination treatments to 20 different plants (5 flowers per plant) which contains 25 zero values (aborted flowers). Should I use the zero values or ignore them and ...
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Difference between pairwise t test and multivariate linear regression results

I got different results when comparing means of different groups using a pairwise t test and multivariate linear regression. ...
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Best linear fit [duplicate]

Which one is the best fit according to these information? fit1 or fit2. I am NOT working with this in an academic context so explanations are not important to me.
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ANOVA - why are the mean squares chi-squared distributed?

I recently came across Analysis of Variance (ANOVA), and it seems that the total sum of squares of the residuals (or "within groups / treatments") divided by the degrees of freedom is Chi-squared ...
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45 views

Understanding the Output of ANOVA in R

I have one response variable $Y$ and one predictor $X$. I am trying to fit a polynomial regression model and try to compare different model with different highest power term, the output of ANOVA in R ...
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How to report my repeated measures analysis?

I've conducted an experiment with 30 participants using a counterbalanced design they performed a task in two slightly different conditions. After both conditions participants were asked to fill in a ...
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Repeated Measures ANOVA or multi-way ANOVA - longitudinal data (SPSS)

In my project, we are "tracking" students' attitudes across three years using a Likert survey, with 5 sections. Students complete a pre- and a post-survey at the beginning and end of each year. ...
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ANOVA - Assumption of Independence

I am also a little bit confused about the assumption of independence. I have the following situation: one continuous dependent variable (radiant power of a medical device) a few independent ...
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How to analyze multiple treatments and measurements?

I've been asked to analyze data from an experiment measuring blood hormone levels from rats after a surgery. Hormone measurements were taken 10 days after surgery and 20 days after surgery. To make it ...
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Place preference determination

I have an open field rectangular chamber. I want to evaluate whether a cue can be associated with food so I designed four groups. Food+cue, food+no cue, no food+cue and no food+no cue (a basic 2x2 ...
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Box-Cox transformation for repeated measures ANOVA (rANOVA) in R

My proposition of the solution Perform Box-Cox-transformation despite of knowledge that obeservations are nont independent and then use rANOVA to estiamte coefficients using the knowledge that the ...
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ANOVA multi-way classification: concise presentation

I have read ANOVA from chapter 11 of 'Statistical Inference' by Casella & Berger. Their presentation is concise. However they stop at one-way classification. Can you suggest some other (chapters ...
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Which option is better: checking 1) normality of data or 2) normality of residuals for Anova?

Two types - data and residuals - are indicated for checking normality for anova.
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38 views

Categorical regression with dummy variables. significant or insignificant that is the question

I'm working on the similarity of categorical regression with exclusively dummy variables and ANOVA. There are lots of references, like Gujarati & Porter (2009), which have mentioned that those ...
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23 views

What are the correct ways to check if a variable is significant?

I've conducted a series of computational experiments varying a set of discrete parameters. I see on the figures that some of the parameters don't affect the result in any consistent way and look like ...
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27 views

how to prove SST follows a chi-square distribution with (m−1) degrees of freedom

It is easy to prove SSE/variance follows a chi-square distribution with (n-m) degrees of freedom. But how to prove SSTreament/variance follows a chi-square distribution with (m−1) degrees of ...
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Two way ANOVA with repeated measure v.s. Linear Mixed Model (in R)

The study design is like following, there are in total 8 subjects (A - H). A-D are female and E-H are male (gender). A-H all do exercises. We measure ...
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Help with (nested?) ANOVA model in R

I would need some help how to write the model formula of an ANOVA in R. The experiment is a 4x4 Latin Square with subtreatments. Each plot has 4 rows and 4 columns, each row and each column contain ...
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Active independent variable

In a study, there are two independent variables - A and B. We only manipulate variable B. Do we count A as an independent variable in our analysis, even though it has not been manipulated?
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can I use Anova test to analyse this table

can I use ANOVA to compare number of days of asthma attacks per month followed for six months between two groups (group 1 and group 2). so we have a 2x6 table in rows we have the months (1st, 2nd, ...
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Difference Between ANOVA and factorial Design

I was wondering about the difference between ANOVA and factorial design ? I have applied the factorial design method for studying some models(in fact in is a model with three factors). I used ...
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Stratified sampling And ANOVA with blocking

Thank you for your reading and maybe your help. I am new in Experiment Design and ANOVA and I do apologize, I am pretty sur this is a stupid question just due to my ANOVA misunderstood. Study ...
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interpret the result of aov in r

I have a data set, which can be created by the following code in R. The data set is called hill. ...
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How do I run a t-test or variance analysis on odds-ratios from multiple binary regressions in SPSS or R?

I am computing a binary logistic regression with two sexes, five age groups and two social status groups as categorical independent variables and the probability of the prevalence of a disease as ...
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using ANOVA to compare values recorded and days of the week

Can ANOVA and tukey testing be used to analysis if there is a statistical difference in means between a value recorded and the days of the week? i.e. to show much lower electricity usage in a work ...
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Test to identify bias in staff recording data - some guidence please

I am involved in a project where staff observe items and record their observations on an input device (ipads in this case). The data set is quite large (+750,000 records). Staff record using radio ...
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Multiple tests plus correction versus ANOVA - is one always better?

A colleague was using three pair-wise t-tests plus Bonferroni correction to detect any differences in the means of three groups. My first response was to tell him to use an ANOVA instead, since my ...
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How to interpret P-value from mixed model and P-value from overall ANOVA?

I fitted mixed effect model with several effects with lme package in R by command ...
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Which statistical test (2 x 2 x 2 three way factorial design, splitted dependent variable)?

I have data collected via a survey and the study is a 2 x 2 x 2 between subject design. For the dependent variable I asked two questions so that it is a split DV = DV_1 + DV_2. My question is, which ...
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How to best analyze a Semantic Differential?

1) How do I code the data gathered from the dependent var (PQ) below in excel for analysis in SPSS? I know how to run an ANOVA afterwards. N=60; Legend: 1 and 7: (extremely), 2 and 6: (moderately), ...
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Minimize coefficient bias in regression with effects coded categorical variables where data is unbalanced and missing

I have a data set with two categorical variables that are effects coded. 6 out of 18 observations do not have records for the first categorical variable. 12 out of 18 observations do not have records ...
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can I use one way anova to analyse my data?

I am doing microtensile bond strength test.Details of methodology : I had 5 adhesive group.For every group I will had 15 sample from 5 teeth. But I randomly mixed this 15 sample and I can't recognized ...
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Testing the total impact of a predictor in a messy model

Suppose I have a regression model with several predictors ind interactions thereof. For concreteness, suppose we are studying a company's data on salaries and we have predictors ...