repeated measurements

  1. P

    is multiple regression the right choice for me?

    I am trying to ascertain the relationship between three variables; two independent and one dependent so I'm fairly confident that a multiple regression would be the correct choice. However I'm not sure if this is correct because of the fact that I have repeated measures. I have repeated...
  2. A

    Comparing categorical outcome variables in repeated measures design

    I am working on an observational prospective longitudinal study with a repeated measures design. The same categorical outcome is measured for five times, for all the participants, over a time period. So there are five outcome (dependent) variables and a few predictor variables. First of all, I...
  3. E

    Ordinal or continuous scale?

    Hello, I have carried experiments where the participants were asked to rate a parameter on a scale. The scale starts from “not heavy” to “heavy”; the subject could mark an X desired position (see enclosed picture). The data is normalized for each participant after each experiment (i.e. the...
  4. V

    repeated measurements - ANOVA, friedmann's test or kruskal wallis?

    Dear all, I am a junior doctor getting involved in medical statistics, of which my knowledge is very preliminary. The problem I face is the following: I want to analyse the effect of a treatment over time, in a group of patients. The medication was started at time 0 and I have...
  5. D

    Normal and non-parametric repeated test data

    Hi All I have done some experimental work and collected data for the conductivity of water with various concentrations of salt. The experiment collected data every 15 mins for 24 hours. Some of the data produced is Normal and other data sets are not normal. Hence I don't know what stats I...
  6. L

    Appropriate model for (repeated) data

    I have some cross-sectional data, where I'm interested in estimating a relationship between the "number of items in use" in sector i of country j and the size of that sector (represented by spending power). There are other control variable. However, I have six (6) sectors and 52 countries. This...
  7. L

    Developing a multiple regression equation with repeated measures data

    Hi, I want to develop a multiple regression equation to predict pollutant concentrations (dependent variable) in runoff using six meteorological parameters (independent variables). My experimental design involves me getting three observations under the same environmental/test conditions...
  8. L

    please help: Is this R-syntax is true?

    I want to ask some confusing in my mind regarding the data analysis: I have conducting the experimental trial in repeated measure by hours as below: Design: Completely Randomized Design--(in green houses)-there are 6 box unit...
  9. M

    Covariance structure in a longitudinal study

    Hi We are conducting a pharmacological trial with repeated measurements of the drug concentration in the blood over several weeks. Due to the imprecision of the method analysing the drug we have small concentration values even before administering the drug (time 0). The problem is that these...
  10. H

    Choice of test in R. Repeated measurements, binary response and missing data...

    I have two treatments and one co-variate (affect the response variable but is also correlated with one of the treatments). Each replicate has been examined for the presence/absence of morphological characters at several time point but there are unfortunately a lot of missing data. What would be...
  11. N

    paired t-test or repeated measurments ANOVA

    Hello Given a group where you run 2 models to obtain a parameter, and the goal is to compare both parameters. But not all individuals tested in one group are tested in another, so there is some variance. If using a paired t-test you execute an F-test to see if the variance is acceptable...
  12. M

    Confirmation of correct test for repeated measures of ordinal data: Friedman's Test

    Dear Stats Community, I performed an experiment in which I measured the behavioral responses on an ordinal scale (1-4) of a group of non-human animals to a series of auditory stimuli (A,B,C,D). The order of the presentation of the stimuli was randomized, but each animal experienced all...
  13. H

    one-way repeated measurements ANOVA

    Dear all, I am new to this forum and fairly unexperienced when it comes to statistics. Maybe you could help me with a problem that I have encountered: My experimental design is as follows: I have a population of cells, which I seperate into 3 different groups of young, middle-aged and old...