All Questions
Tagged with mixed-model hypothesis-testing
156 questions
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Test of variance component in one-way random effects ANOVA
I have a question regarding the adaptation of the following to the test of single variance components laid out in Raudenbush and Bryk (2002, p. 63-64). The hypothesis is about a single component of ...
1
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1
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29
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Statistical model / test for difference in change over time for two conditions
I have data from an experiment that looks like this:
rep 1 T=0
rep 2 T=0
rep 1 treatment
rep 2 treatment
rep 1 control
rep 2 control
0
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7
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4
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8
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The ...
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1
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66
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What should I call this design?
Tha someone help with this question?
A study has 3 fixed effects A, B, and C and one random factor ID. Factor C (two levels) is determined by each ID's inherent characteristic (so basically two groups)...
1
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1
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55
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Two way anova or paired t-tests
i am looking to see if there is a difference in dissolved oxygen levels between pool surface (S) and bottom (B) samples at four sites (an up and downstream site in two creeks). There are 3 replicate ...
1
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1
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30
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Testing the effect of a continious IV on DV, in order to explain group differences
I would like to ask a question regarding an analysis I’m planning and it might be a basic question so, apologies in advane.... To describe the situation: There are two groups of participants in my ...
3
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1
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67
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Choose to resolve and report only some hypotheses
I have carried out a 2 x 2 x 4 x 4 experiment with 12 subjects to perform a linear mixed model. Would it be correct to perform the complete analysis but report only the results of the 2 x 2 ...
7
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2
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171
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(Mixed-)model specification and comparison for testing hypotheses concerning continuous ratings
In a behavioral study following a within-subjects design, subjects of various levels of musicality (years of education) gave continuous liking ratings of three audio stimuli, each under three ...
0
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1
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44
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Test for significant difference between two groups measured across time
I have two groups of time-dependent samples whose measured value changes nonlinearly with time. There are 3 samples in group A and 3 samples in group B. An example of my data is illustrated below.
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3
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1
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217
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Mixed effect logistic regression model
I am very new to the world of statistics and I need some help. I am currently doing an experiment and I have to analyze the data, but I honestly do not know anything about statistics (I have tried to ...
2
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0
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70
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How well does my model fit? Specifying a null-model in non-linear mixed models
I want to fit a model y ~ b * exp(-exp(a) * x), but including a random effect, with this data:
...
5
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1
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53
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Is repeated measures appropriate for testing for a difference in repeated paired group measurements?
I'm new to repeated measures and am trying to understand how it maps to lmer.
I have measurements from two time periods:
$t_1, t_2$.
At each measurement period, the same 50 different foods are scored ...
2
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2
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246
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Determination of sample size vs. repeated measurements in experimental design
NOTE: Revised question following suggestions from others. Thank you for taking the time to help me refine this question to make it answerable!
Background
I want to compare the performance of two ...
0
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0
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16
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How to get a site-adjusted (clustered) p-value
I'm working on a problem involving clinical trial data and am trying to account for the different clinics patients were treated at. In papers I've read, authors present p-values for differences in ...
1
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0
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64
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Comparing mixed effect models fitted to two different datasets
I have two different time series data which are the results of running a simulation model with different sets of parameters and configurations. The datasets each contain 100 time series which indicate ...
3
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1
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695
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Understanding Mixed Effect Models visually with some questions on P-value calculations
I've been tackling the concept of Mixed Effects Models on and off for the last 9 months. Every time I would give up and come back later to try and understand it again with my basic statistics ...
1
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1
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92
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I think this data should be analysed using a linear mixed-effects model, but it doesn't seem to make sense when using buildmer? [closed]
I can't give the exact data because it's sensitive, but I have the following information about the data:
3 continuous variables which are within subjects (scores for test separated by time).
1 ...
5
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2
answers
796
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Different results between ANOVA and Linear Mixed Effects
A set of subjects from two groups are requested to perform a test after a sleep session of type A and then after a sleep session of type ...
2
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1
answer
76
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Paired t-test on dependent samples
I have a set of paired observations, corresponding to patient blood pressure before and after a treatment. I'd like to test for the significance of the treatment by conducting a paired t-test (or ...
0
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0
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43
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Hypothesis testing with data which is both pair and repeated-measures
Suppose I conduct an experiment to test the hypothesis that treatment A suppresses protein X. I am fortunate in that I work on kidneys, which come in pairs, however I am unfortunate in that I don't ...
1
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1
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68
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Using one linear model to test multiple hypotheses
Let’s assume the following:
I have data of 100 subjects each performing 100 trials of a reaction time task
At each trial, I measured the reaction time (RT) and a specific brain signal (BS)
The RT and ...
1
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1
answer
40
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Interpreting Mixed Model ANOVA
In a 3 (condition) X 2 (time) mixed model ANOVA. If I hypothesised that anxiety in group A will increase from time 1 to time 2 and my results found no significant interaction but a significant main ...
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1
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83
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Mixed Effects or other Model for Binary Interventions and Binary Outcome
I'm trying to understand the impact of 2 different binary interventions on the completion rate of around 10 courses. The courses all have different baseline completion rates. Intervention one was ...
7
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1
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127
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Explaining a Mixed Effect Model to a Non Statistician/Mathematician
I'm not a statistician, but I do have a basic understanding of biostatistics in the context of medicine and clinical trials. However, recently I came across a trial that is using a statistical method ...
4
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1
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262
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What kind of model is best suited for this type of data and research question?
I have data for hundreds of individuals over several (often tens) of years. My dependent variable is a binary event that may or may not have happened for each individual in some given year. The event ...
0
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1
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366
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Incorporating a random effect to the null model
I would like to decide if it is reasonable to include a factor variable to the null model I.e y ~ 1 VS y ~ (1|x)
I haver read this answer https://stats....
0
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0
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30
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Significant t-value but bayes factor showing favour towards null
I am currently trying to build linear mixed-effect model to compare continuous dependent variables between categorical independent variables (like conducting ANOVA), but with random factors (to remove ...
3
votes
1
answer
62
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Should all the levels of a fixed factor be present in all the experimental trials?
I would like to analyze the output of 11 field trials dealing with the disturbance to soil after logging operations. The goal is to check if there are significant differences between two machinery: ...
2
votes
1
answer
127
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How to analyze a dataset with unequal treatment distribution?
I’m looking for the best way to analyze a data set. The experiment was conducted at two different locations, X and Y. The experiment at location X was conducted in one year (2014), whereas the one ...
1
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0
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44
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Colinear nested variables and hypothesis testing for higher-level variable in non-randomized experiments
We have a study setup for testing a new learning treatment, which basically looks like this:
We have 4 tracks (same university course taught by different lecturers). In two of these tracks, the ...
2
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1
answer
92
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Which test would take advantage of comparing large sample groups with replicates?
So, the data is comparable to height of individuals within Africa and Europe, but each group (Europe, Africa) have multiple replicates (3 x month sampled).
Each replicate is ~100,000 individuals.
A ...
2
votes
1
answer
128
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Correct inference on hierarchical data
I am doing an experiment on cell cultures comparing how some treatments affect the parameter of the cells. I have 3 replicates of the culture for each treatment, and in each culture, I measure the ...
2
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1
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77
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hypothesis testing with data that are not equally independent
I think the easiest way to explain my question is with an example scenario:
Let's say we have 10 groups of 5 people and each group is in an identical circular room in which we are allowing them to ...
0
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0
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73
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How to compute Cohen's d and p-value for comparison of least squares mean from two different mixed models?
I have two randomly assigned treatment interventions (A and B), and two subgroups of individuals (X and Y). This is a longitudinal study with dropout. I want to test whether the outcomes of ...
2
votes
1
answer
224
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How to simulate type I error for random-effects model?
Building upon this post How to simulate type I error and type II error. I would like to simulate type I error for a random-effects model I generated. The statistic of interest is standard deviations ...
2
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0
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244
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Why duality of confidence interval and hypothesis testing fails in random effect test for presence random effect?
I am reading Faraway's Extending the linear model with R chapter 10 section 2.
"In this case, the lower bound is zero. This is not surprising given our earlier
uncertainty over whether there ...
2
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0
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198
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Testing for between-samples factor with linear mixed models
I have data from an experiment including 5 biological replicates, each of which has 3 technical replicates. These 5 samples are divided into 2 groups (condition a and contidion b). My goal is to test ...
9
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1
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773
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Confused: Why is lme4 changing techniques from Wald F tests to Wald Chisquare?
I've constructed some LMEMs that use dichotomous variables and their interactions as regressors, and I've become confused by the output. When I only assess a single interaction, using the code below (...
1
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1
answer
334
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Can you include between-subject control variables in random effect structure of mixed models if they are not fixed effects?
I tried finding similar cases and questions but failed and got even more confused because the answers seem to depend on when the questions were asked due to changes in the lme4 package. So I'm sorry ...
2
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1
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568
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How to interprate random effects in an lme model in R [closed]
I am having trouble understanding the results of my lme model. Could someone tell me how to understand the random effects?
Here is my model:
...
2
votes
1
answer
2k
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Mixed effects model adding covariate vs adding random effect
I am currently looking into mixed effect models and I am trying to understand the difference between adding a random effect and adding a covariate to a linear model.
Consider this example:
...
1
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1
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35
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Can I "discard" p-values from my linear mixed model?
I have a linear mixed effects model as follows in R:
model.int = lmer(value ~ group * category * time + (1|patient), data=modeldata)
anova(model.int) then gives me ...
3
votes
1
answer
204
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What statistics can be used to analyze and understand measured outcomes of choices in binary trees?
I am conducting biological research on animal behavior. There is an arena set up like a binary tree. End nodes are sources of food (e.g. smells) or stimuli that can mix. The animal (or a group of ...
3
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2
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324
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What statistical test should I use with count data? [duplicate]
In my experiment, participants are shown 4 images (A, B, C, D) that they have to rate on a 5 point scale. So my data looks like this:
particpant1: A 5, B 3, C 3, D 1
p2: A 4, B 3, C 2, D 4
p3: A 4, B ...
1
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1
answer
93
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Hypothesis testing with time autocorrelated data
I have a dataset such as the following:
...
5
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1
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555
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Paired and repeated measures! Now what? ANOVA or mixed model?
I have a simple setup. I have 10 patients and I would like to test the effect of a certain drug on kidney function. Each patient will serve as his own control and intervention.
First for the control ...
2
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0
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451
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How would I conduct an equivalence test in R from an lmer() model?
Lets say I have a null result, as in the following example:
library(lme4)
iris$Rand <- rnorm(150)
m <- lmer(Petal.Width ~ Rand + (1|Species), data = iris)
...
1
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1
answer
36
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What options does a person have for showing evidence in favour of the null hypothesis?
I have a linear mixed-effects model with a theoretically important null result. Of course a reviewer asked for a Bayesian approach to "show evidence" for it.
However I am struggling with ...
0
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1
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305
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Interpretation of p-values from LLR-test in mixed models
Let's say I did a GLM including one categorical factor (let's say with three levels, so two indicator variables). In such a case, I understand that the interpretation of the p-value associated with ...
1
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0
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1k
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Using clmm() for ordinal dependent variables
I have a 2 (Complexity: 1=Simple vs. 2=Complex) by 3 (Type: 1=A vs. 2=B vs. 3=C) design, where each participant completed separate tasks counterbalanced across the 6 conditions, and then gave a rating ...