Tagged Questions

2
votes
1answer
162 views

Moderation in repeated-measures design?

Context: Both dependent $(Y_1,~Y_2,~Y_3)$ and independent $(X_1,~X_2,~X_3)$ variables were measured repeatedly at three time points, $\text{Time}_1$, $\text{Time}_2$, and $\text{Time}_3$. Moderator ...
0
votes
0answers
41 views

Repeated measures data

Suppose you have data where you measure a subject at 10 different time points but some subjects are measured at less than 10 time points. Can you still apply standard methods to model observations at ...
4
votes
1answer
343 views

Multiple regression with repeatedly measured independent variables?

Design and hypothesis: we measured wellbeing at Time-1 and Time-2, we want to see whether factor A (measured at Time-1 and ...
3
votes
0answers
67 views

Modeling measurement error (reliability?) using repeated measurements

I have a measurement protocol that seeks to characterise the visual sensitivity of a subject. I would like to assess how reliable the measurements from this procedure are. I have measured a small ...
3
votes
5answers
275 views

Conversion between units of measurement

I have two different measuring instruments, A and B, both measure the same physical quantity but with different unit of measures: $u_A$ and $u_B$. A is a reference instrument. I measured a reference ...
2
votes
1answer
128 views

Reference for dummy variable regression for repeated measurements

I want to analyze some repeated measures data using a dummy variable for each measurement unit. This is one approach to deal with the fact that the data is not i.i.D. when repeated-measurements are ...
2
votes
3answers
294 views

Logistic regression with repeated measures?

I would like to make a prediction for a (new) subject to have a certain outcome given the historical data and the model: ...
0
votes
1answer
138 views

Comparing means - 2 repeated measures variables, controlling for covariate with heterogeneous slope

I have a 2 level repeated measures DV of accuracy, and a covariate of response bias. As response bias increases, accuracy level 1 increases while level 2 decreases. I want to see if there is a ...
0
votes
1answer
1k views

Linear regression with repeated measures in R

I was unable to figure out how to perform linear regression in R in for a repeated measure design. In a previous question (still unanswered) it was suggested to me to not use ...
2
votes
1answer
848 views

Comparing means between two groups over three time points

I have two groups of ten observations each, where the weight are measured at three different points in time. Let´s say baseline, 2 months and 5 months after baseline. Now I would like to draw a ...
2
votes
2answers
268 views

repeated measures regression

I was hoping that I could get some feedback in terms of keywords I should searching for, or concepts I need to consider with the following: I have non-experimental data that I would like to model in ...
1
vote
2answers
136 views

Which statistical method should be used in the study of stability of an enzyme?

I did a study monitoring the stability of an enzyme exposed to different conditions over time. Each day for 30 days, an aliquot was taken from each storage sample and analyzed in duplicate. I wanted ...
6
votes
1answer
404 views

How to specify Bayesian mixed effects model in BUGS

I posted this earlier in the week then retracted the question when I found a good source, not wanting to waste people's time. I haven't made much progress I'm afraid. In trying to be a good citizen ...
2
votes
2answers
81 views

What type of regression analysis is best to model the relationship between self-efficacy and activity level over three time points?

I am conducting an orthopedic study to predict improvements in activity level (dependent variable) based on a type of self-efficacy scale (the independent variable). There are, however, other ...
3
votes
2answers
98 views

How to analyse a study where measures are taken repeatedly from right and left legs in five walking conditions?

There are 13 subjects in this study, each subject was "repeatedly measured" right and left legs on five walking conditions. The variables of this data set is: ID, Y, Leg, Conditions. The research ...
11
votes
8answers
3k views

Is it valid to include a baseline measure as control variable when testing the effect of an independent variable on change scores?

I am attempting to run an OLS regression: DV: Change in weight over a year (initial weight - end weight) IV: Whether or not you exercise. However, it seems reasonable that heavier people will lose ...
5
votes
1answer
158 views

How to test the effect of condition on change scores for a possibly ordinal dependent variable?

I have a categorical independent variable (two levels: condition 1; condition 2) and ordinal(?) dependent variables (numerical magnitude shifts (e.g. -3 if there was a decrease in number magnitude ...
2
votes
0answers
123 views

Is it allowed to incorporate static covariates in Mixed effects models with time series data?

I was recently told that it is not allowed to include static covariates in mixed effect models. I can believe that this could be true, however, when I have time series data, and season is a grouping ...
7
votes
2answers
797 views

Longitudinal data: time series, repeated measures, or something else?

In plain English: I have a multiple regression or ANOVA model but the response variable for each individual is a curvilinear function of time. How can I tell which of the right-hand-side variables ...
8
votes
1answer
262 views

Can slopes in linear regressions be used as the independent or dependent variables in other regression models?

I have 100 patients and each patient have 10 longitudinal serum creatinine measurements. The estimated glomerular filtration rates (eGFR) were calculated from a MDRD formula comprising gender, age and ...
1
vote
1answer
176 views

Regression with repeated data

I have a question regarding regression analysis on a dataset were the input values generate different results over time: e.g. 1 2 2 2 3 5 4 1 2 5 3 8 How would ...