# linear mixed model

1. ### Characterising continuous effects in linear mixed models as fixed or random

Hello, I've started to learn about linear mixed models, and I'm a bit unclear on the distinction between fixed versus random effects when the effect is continuous. Let's use an example where participants react to pictures (dependent variable: reaction time) and these pictures are described by...
2. ### Help with interpreting Linear Mixed Models - ignore p-value, just go on B-estimate?

I have been given advice that I should always interpret the relationships shown in the model of best fit, from having run a linear mixed model, regardless of the p-value. I want to do this anyway, as some of my moderator/predictor variables didn't quite reach significance. But I know my...
3. ### Are effect sizes required when reporting a Linear Mixed Model? If so, how are they calculated?

I have undertaken an RCT and, given multiple irregular time-point measures of the DV, have used linear mixed models to analyse the results and include moderator/predictor variables. CONSORT is quite emphatic about the reporting of effect sizes. However, SPSS does not produce these for linear...
4. ### SPSS Linear Mixed Model repeated covariance type

Hi everyone, I need your help with regards to specifying repeated covariance type in SPSS. I am trying to build a Linear Mixed Model in SPSS with the subject being 'borough' and repeated variable being YEAR . My dependent variable is the number of people claiming housing benefit, per year (for...
5. ### Mixed model analysis for group differences if some participants but not all are family members of eachother

Hi! I have a question. I'm very new to mixed model analysis and I'm trying to find out how I can use it to solve my problem. In my research project, I have seen two groups of children (cases and controls) and they performed all sorts of psychological tests and filled out questionnaires. Now I...
6. ### Significant interaction no significant comparision

Dear community, I did a linear mixed model full factorial with 2x2. I use the linear mixed model like an ANOVA and I have one significant main effect and a significant interaction effect.To solve the interaction I split my data by one variable and analyze the main effect by the other variable...
7. ### Creating a time variable in SPSS

I have just started with my research project. My supervisor asked me to do some simple stuff with the dataset in SPSS. Unfortunately, I don't have a clue of what I'm doing in SPSS. Could anyone help me? I'm supposed to do a mixed linear model analysis, but right now I'm just preparing the...
8. ### Nested within-subjects repeated measures stats?

Hi people, I am having some confusion over how to carry out the stats for my experiment. In the experiment, there is two condition of teaching method "prof-generated" and "student-generated" and the DV is students' quiz scores over 4 quizzes. As I carried out the experiment in a real...
9. ### How to compute r squared in linear mixed model

It's kind of urgent. i need to hand out my thesis in 3 days from now :/ Can someone explain me how to computer r squared in linear mixed model? i included a photo of the model output Thanks [1]: https://i.stack.imgur.com/I9D5k.png
10. ### General linear mixed model - 5 years

Dear all, every help is highly appreciated! I have a data set that looks like the one I attached to this post. I have five independent variables for each company (for each time period one). Now I need to know, if the values significantly increase over the time of five year. In other words I...
11. ### Two-Level Model in Matrix Notation

A two-level model, with one explanatory variable at the individual level (X) and one explanatory variable at the group level (Z): Y_{ij}=\gamma_{00}+\gamma_{10}X_{ij}+\gamma_{01}Z_{j}+\gamma_{11}X_{ij}Z_{j}+u_{0j}+u_{1j}X_{ij}+e_{ij}\ldots (1) correlation between u_{0j} and u_{1j} is 0 . The...
12. ### Specifying formula of lmer() function in R .

Am I specifying my lmer model correctly ? Say I have one independent variable (X) at individual level and one independent variable (Z) at group level. Both are continuous variable . If the model is...
13. ### What to do with unequal sample sizes?

I am working on this time-effect project in which we pulled data at different time points from a big old data set. The issue is that all subjects were sacrificed at different times after treatment. So I have 16 samples at time 1, 10 samples at time 2, and so on. I am going to do Friedman test...
14. ### Need help choosing a statistical method/model

Hello, I am currently doing a study on the defensive behavior of the European Grass Snake, and I was hoping someone could help me figure out which model to use to analyze my data. I have 3 categories of dependent variables - 1) Pre-Capture Behavior 2) Post-Capture Behavior 3)...
15. ### Linear Mixed Model Analysis with multiple fixed factors

Hellow, Here is a question on linear mixed model analysis for an intervention The study composed of two group of subjects who receive a DrugA versus Placebo and their Cholestrol and Sugars measured at baseline, six months and 12 months. So i did a simple analysis to detect the changes with...
16. ### Need help with linear mixed modeling in SPSS

So I've looked a quite a few tutorials and forums to see if anyone has posted something similar to the dataset I'm analyzing, and it doesn't seem like anyone has. I more need someone to tell me if what I'm doing is right or not. My data is looking at maternal cytokine levels during the...
17. ### Fitting of a linea mixed model

Hello I'm trying to modelize the diving depth of birds according to categorical (sex, age class: adults/subadults) and conitnuous parameters (temperature, salinity). The frequecy distribution of this data looks like this: many many many dives between 0-50m deep, some between 50-100m deep and...
18. ### Correlation?

Hello all, I have accuracy scores on 6 different tests. I have calculated the percentage of the accuracy in each test so that each of the tests has a score on the same scale (0-100%). I want to see how well do each of the 6 different tests correlate with a 7th test. I have been told I should...
19. ### SPSS linear mixed model for repeated measures at two levels

Hi! I'm struggling with a basic question for which I couldn't find an answer in the texts and papers on LMM in SPSS. This is the basic structure of the dataset: - outcome = grip strength - effect of interest = injury on dominant vs non-dominant side The source of repeated measures...
20. ### simulating a repeated measures ANOVA with mixed linear model analysis

Hi all, I have a data set with two within subject variables, word category (2 levels) and time (3 levels), and I have a between subjects variable, namely group (2 levels). My dependent variable is reaction time (RT). If I run three separate repeated measures ANOVA for the three different...