linear mixed models

  1. M

    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. T

    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. T

    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. P

    Repeated Measures ANOVA as Linear Mixed Model

    Hi there, I have a study in which one group of subjects are completing a face recognition task with an eye tracker. First, they learn a set of faces, one at a time. In the testing phase they are tested on their memory for those faces, one at a time, with some faces being targets and others...
  5. B

    SPSS 23 Linear Mixed Models -- Why is the Bootstrapping feature grayed out?

    Using SPSS 23 to run linear mixed models. I've set up perfectly good models that run beautifully, but I want bootstrapped estimates and the button for that is grayed out. What is wrong with this program?!?!
  6. R

    Linear Mixed Model, a Regression type Statistical Analysis or other?

    I have performed a study on stability where my outcome is continuous and the two inputs are ordinal. Essentially: I am trying to understand if the weight location in a backpack (high, medium, low) and the grade of the road (0%, 5% and 10%) are related to significant differences in stability...
  7. M

    random effects in mixed models

    Hello I am not very familiar with mixed models --- I have been reviewing the various tutorials on the web but still am not sure if/how to specify my model, even to start with. I have a relatively simple design: - two weight groups (non-random; normal/obese) -- randomized within each group to...