1
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1answer
66 views

How do I “nest” data in a mixed-effects model? and MANY related questions about mixed effects models!

I treated 80 people with drug X and 80 with drug Y. I presented the drugs to them in groups of 10 (meow groups). The drug was consumed for 15 weeks. They reported the severity of their headaches (from ...
1
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0answers
15 views

Linear Mixed Models with variable time points in SPSS

I am analyzing a clinical study measuring patients' symptoms and brain structure sizes over three time points. The "visits" should be at baseline, 3 months and 12 months but they vary considerably and ...
1
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1answer
61 views

Statistically prove the effectiveness of a treatment using GLM repeated measurements

I have two lots of samples: one is the control lot and the other undergoes some treatment. I did three measurements for the samples: one at the initial time (T1) ...
0
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0answers
4 views

Saving level 2 residuals in SPSS [migrated]

I am estimating a twolevel regression model in SPSS using the mixed procedure and would like to plot the level-2 residuals; however, I only get residuals for the observations at level-1. Can anyone ...
1
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0answers
27 views

random effect in mixed linear model SPSS

I am using a mixed linear model to analyze the effect of two types of treatment on symptoms. The two treatments were administered in smaller groups (clusters), and delivered by several doctors, so I ...
1
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0answers
85 views

What do the tests of model effects and parameter estimates really tell (when an interaction is defined)?

A couple of times in LMM or GEE (with SPSS, though I doubt that matters – and might occur in other analyses as well, but these are the ones with which I have seen it) I have seen something that seems ...
1
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0answers
17 views

Need help with proper syntax for SPSS Mixed [closed]

I am having trouble building my model properly, and I was hoping I could get some advice here. I have a 2 (S: P vs. D) x 3 (ET: CA vs. CO vs. AD) between-subjects design. Participants were run in ...
0
votes
1answer
75 views

How do I model repeated measure + random effects with SPSS mixed

I'm having trouble understanding what a correct model for my data should be, and also if it would even be a good idea to make it a single model. At the basis it is a rather simple regression model ...
1
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0answers
44 views

Model comparison in SPSS

I have two models with 24 variables in each. I want to see how adding an extra variable (the variable in study) affects the outcome. I used generalised linear mixed models for both models.(GENLINMIXED ...
0
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0answers
74 views

Mixed Model t Test (Toothaker’s t-Test)

I'm trying to do a follow up test for a mixed model ANOVA, and I figured that I need do a Mixed Model t test also known as Toothaker's test. I just don't know how do it. I was wondering if anyone has ...
0
votes
0answers
69 views

Mixed Model ANOVA interpretation

I am using SPSS to analyse the 3-way mixed model ANOVA of my study. I have split my variables down to interpret simple interaction effects and found that whilst the graph displays an interaction ...
2
votes
1answer
217 views

Using AIC to select between models that use nested and non-nested variables

I'm using SPSS to try and find a mixed model that adequate explains the data that I have. Two of the explanatory variables are closely related ('Sample group' and 'individual'), as an individual is ...
1
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0answers
79 views

Mixed linear models with exactly the same AIC?

I have a dataset in which I measure the response variable of a number of individual animals. I used this response variable as the dependent variable in a linear mixed model, for which I have 5 ...
0
votes
1answer
450 views

Random effects in mixed models

I am not very familiar with mixed models --- I have been reviewing the various tutorials on the web but still am not sure how to specify my model, even as a starting point for comparison. I have a ...
1
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0answers
26 views

How to test for differences between groups over time when N is less than the number of levels

I have done a live cell imaging time course over 24 hours, and have a result for each hour. I have 3 experimental groups and 1 control group. What I want to know is if any of the experimental groups ...
0
votes
1answer
125 views

Personality traits as fixed vs. random effects in a repeated measures mixed model

We performed a randomized controlled trial. I am interested in anxiety levels (dependent), treatment (meds vs. ultra-dance therapy), and personality variables (agreeableness, neuroticism, weeaboo). We ...
4
votes
0answers
138 views

Interpretation of mixed model with repeated measures

I have performed the following experiment: Two genotype groups of two different ages were monitored in the presence of three drugs one after the other. So, each subject after a control period received ...
3
votes
0answers
121 views

Is it possible for my mixed model results to be the same as those for a repeated measures ANCOVA? Why don't I get the same results? SPSS

The experiment: Two groups of children perform tasks with three levels of difficulty at two different time points and brain activity is measured. All of the children perform all of the tasks and do so ...
1
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3answers
1k views

Interpret significant interaction but no main effect in repeated measures ANOVA

I have a model in which two groups are measured on one DV at pre- post- and 3 months following an intervention (the control group did not receive the intervention). I have an interaction effect, which ...
0
votes
0answers
102 views

How do I perform a Mixed model analysis on my data in SPSS?

In my thesis I'm trying to discover which factors influence the CSR (corporate social responsibility, GSE_RAW) behavior of companies. Two groups of possible factors ...
2
votes
1answer
446 views

Why do coefficients and significance levels change so much in my OLS? Do I need MIXED model instead?

Please consider the following OLS model: As a rule of thumb, a VIF score of max. 5 is considered acceptable collinearity in most fields. So for the better part I believed this model to be quite ...
1
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0answers
303 views

ANCOVA (GLM) versus Mixed Linear Model with covariate measured at both pre- and post-treatment (in SPSS)

I'm trying to analyze a pre/post study with 4 treatment groups. The Dependent Variable, Speed, measures how quickly a person's facial expression reaches peak intensity; this measure is normally ...
1
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1answer
580 views

Interpreting SPSS mixed linear model output

I have a problem interpreting the output of the mixed model procedure in SPSS. I found a couple of threads dealing with similar problems, but none helped me solve ...
1
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0answers
222 views

Mixed model repeated measures, nested

I have a study in which I have 3 groups of crews (4 crews in each group) in which there are two people (L/R). Each crew experienced 4 lighting treatments (D1-4), once in one position, and again in ...
3
votes
1answer
568 views

Comparing groups at different time points within repeated measures study using SPSS

I have done a RCT (randomized control trial) of an intervention (which is of 6 week duration) versus control. The outcome measure (an exercise test) has been tested pre-intervention (Pre), immediately ...
3
votes
1answer
272 views

Checking normality of residuals in 2x2 mixed methods ANOVA

I am running a 2x2 mixed method ANOVA (with one between-group factor and one within-group factor - time 1 and time 2). I want to check whether the assumption of normality of residuals is met. When I ...
1
vote
0answers
350 views

Effect sizes from LMM

My question is, how to get effect sizes for a linear mixed model? I am using the following model in SPSS: ...
2
votes
2answers
98 views

“weird” results from multilevel analysis

I am examining the effect of a group variable (with five levels) along with other predictors on achievement growth using SPSS Mixed Model. The descriptive statistics showed a consistent pattern on ...
0
votes
1answer
207 views

Difference between predicted values and estimated means

In SPSS linear mixed model (analyze->mixed model->linear), one can opt for predicted values. In the SPSS data file, a column is added with new data, i.e., the predicted values. When I run a linear ...
3
votes
1answer
363 views

Variances not homogeneous problem in ANOVA mixed between-within subjects, too bad?

I'm conducting a 2x3 mixed between-within subjects ANOVA (group x time). I have 20 participants, 10 for each group, who undergo all the 3 measures over time. Levene's test of equality of variances is ...
0
votes
1answer
1k views

Normality test for anova mixed model in SPSS: I did it in two ways but the results are contrasting

I'm conducting an ANOVA mixed model 2 X 3 (group X condition). Right now, I'm checking for the assumptions of ANOVA, such as normality. I should check indipendently for group and condition, right? I ...
5
votes
2answers
3k views

Post hoc test in a 2x3 mixed design ANOVA using SPSS?

I have two groups of 10 participants who were assessed three times during an experiment. To test for differences between groups and across the three assessments, I ran a 2x3 mixed design ANOVA with ...
0
votes
0answers
421 views

Which test to use in a single group pre- and post-treatment analysis

I am attempting to analyse pre-existing data (using SPSS). I have one group of participants, 4 quantitative, non-parametric outcome measures, and am looking to see if there is a change in outcomes ...
1
vote
1answer
477 views

Mixed linear model with repeated measures in SPSS

I'm trying to run a mixed linear model analysis with SPSS. When I try to run the analysis, SPSS gives the following error message: ...
2
votes
1answer
2k views

How to interpret an interaction effect in SPSS output for a repeated measures anova with between and within group factors?

I have conducted a repeated measures ANOVA, with 2 factors: One between factor (Ex_control: exercise intervention versus control) One within factor (...
6
votes
0answers
114 views

Balanced repeated measures design

Okay this is my problem: I have 12 participants. Each participant spent 3 nights in my lab doing a reaction time task at four timepoints during the night(12, 1, 2 and 3 oclock), with one week ...
11
votes
3answers
6k views

Difference between generalized linear models & generalized linear mixed models in SPSS

I am wondering what the differences are in SPSS between analyze-> generalized linear models-> generalized linear models & ...
2
votes
1answer
180 views

How do I predict subject mean (w/ error) with repeated measurements in SPSS?

Context: say I am trying to determine the concentration of a chemical, so I take known concentrations of the chemical and make a standard curve (6 measurements per standard) then measure my unknown 6 ...
4
votes
1answer
661 views

Inconsistency in mixed-effects model estimation results (Stata and SPSS)

For my thesis there's a big chance that I will need some sort of mixed-effects specification. I have some (non-syntax) experience with SPSS but feel that it won't suffice for my analysis. I have very ...
3
votes
0answers
74 views

Time series with 3 factors from different sources

I've been asked to try to do a preliminary 'meta-analysis' of some data, but while comfortable with maths I don't have much experience with stats. I'm hoping to get some feedback with what I have ...
1
vote
1answer
515 views

How to interpret 3-way interaction with one continuous variable in mixed model

I have problems interpreting the direction of the effects in my model. Can you help me with this? I conducted an experiment which includes between subject factor: group=2 (coded as 0-1) within ...
0
votes
1answer
347 views

Multilevel model with an ordinal outcome

I have a data set from a survey of health problems and annoyance by traffic noise in people living in residential buildings, with "5-point scale answer" questions. I want to perform a multilevel model ...
1
vote
0answers
1k views

How do I run a Mixed Model repeated measures analysis in SPSS to evaluate intervention effect while controlling for school?

I am trying to evaluate the effect of an intervention. I have a group-randomised rct design and have established that I have a design effect and therefore need to control for school. So far I have ...