ancova

  1. H

    ANCOVA: how to recreate equation based on SPSS output?

    Hi all, I performed an ANCOVA with 3 covariates (Analyze>GLM>Univariate…). I would like to use the output that SPSS provides to calculate the adjusted values for my independent variable for each individual. I am trying to do this by figuring out the equation that SPSS uses to calculate the...
  2. A

    Binomial response variable with 3 continuous and 1 categorical predictor. Best test?

    Hello I have a binomial response variable. Predictors are composed of 3 continuous variables (the results of a Principle Components Analysis of habitat structure variables) and 1 categorical variable (habitat type e.g. grazed or ungrazed). I want to test whether the 3 habitat variables have...
  3. C

    RM ANOVA vs. ANCOVA question

    Hi stats friends! I'm trying to decide whether to use an RM ANOVA vs. an ANCOVA to test a question and I could use your help. Participants were randomized into 3 groups (categorical between-subjects IV: Factor A), and two continuous variables (let's call them B & M) were measured at 3 time...
  4. M

    Which approach to use? Repeated measures with a covariate

    Hi, I hope that someone can give me a pointer please. I am trying to determine which is the most appropriate test to apply to my data. I have some data which were originally formulated for a 2x2 Repeated Measures ANOVA. I was particularly interested in the A*B interaction. However, having...
  5. T

    2X2X2 design.. what statistics should I use?

    Hi, I am doing a research with a 2X2X2 design: Between subjects (Positive Mood VS Negative Mood) Within subjects (Positive Stimuli 1 VS Negative Stimuli 2) Within subjects (Positive Stimuli 2 VS Negative Stimuli 2) I have a range of dependent variables including response time/ decision...
  6. L

    Evaluating data via a three-way (2 x 3 x 4) ANCOVA

    Biomedical researcher here, trying to figure out how to analyze the results of a study on cell culture conditions. Three IVs were chosen: compound A (2 levels), compound B (3 levels), and compound C (4 levels). Cells were grown in microplate wells, 4 wells for each of the 24 permutations of the...
  7. K

    How to determine significant diff or not btwn slope and intercept of two datasets?

    Hi, this is for some research I'm doing in a lab, and I cannot for the life of me figure out how to determine if the two regression lines' slopes and intercepts are significantly different or not (I'm hoping they aren't!). From looking at the graph below, it seems obvious that they should not be...
  8. M

    Assumptions in ANCOVA, and consequences of violating them

    I ran an ANOVA with 4 predictors (2 categorical, 2 continuous) and 1 covariate (continuous). Including the covariate did not significantly alter the main effects of the ANOVA when it was run without the covariate, so I concluded that the covariate did not need to be included in the overall...
  9. A

    ANCOVA woes

    I'm having real trouble interpreting the output from my ANCOVA. I have two conditions control and experimental, my dependent variable is state self-esteem and my covariate is trait self-esteem. In the model I have included gender and condition as a fixed factors and the covariate as trait...
  10. S

    Non-Equivalent Group Statistical Analyses - is ANOVA appropriate?

    Hi there, I have pre/post data on the same tool for two different populations (Group A: Higher needs, Group B: Lower needs) and two different services (Intensive counseling for group A, Brief counseling for group B). Other variables include age, gender and length of service. Would it be...
  11. P

    SPSS: How to decompose interactions in repeated measures ANCOVA?

    Hello everyone, I have a problem, too. Anyone here who could help me? I conducted a study with three categorical within-factors and one continuous personality variable: topic (1,2) x gain loss framing (1,2) x achievement security framing (1,2) x personality I know how to use the...
  12. A

    Two questions about my study

    I have 2 questions about my study: 1. I did a study but now I have only one male and the rest are females. I have like 19 sample size. So should I exclude the male subject or keep him and use an ANCOVA? 2. When i use an ANCOVA, I get the means and SE from SPSS, but no SD. Can I use that...
  13. N

    four-way repeated measures ancova

    Hello! I want to perform an four-way repeated measures ANCOVA, but I'm not quite sure how. I want to analyze the following: Four categorical independent variables: 2 dichotomous, 1 with 3 categories, 1 with 5 categories. Two interval control variables. One continuous dependent variable...
  14. R

    Use z-scores in Repeated Measures ANCOVA?

    Hi everyone, My dissertation has participants answer three questions at four different timepoints in a video. For each timepoint, I have averaged the three questions for an average response per timepoint (4 scores). I also have a dichotomous between subjects variable, and two continuous...
  15. A

    Several covariates in ANCOVA?

    I am running a study where I compare changes in brand attitudes across time for four brands, all within subjects. Between Time 1 and time 2, participants see some information and i want to see how it impacts their rating of each brand. I want to use ANCOVA to control for Time 1 brand attitudes...
  16. S

    Want to plot line to subgroups for relation between one of the IV and the DV

    Hi all, I will try to explain my case as detailed as I'm able to... I have measured on 11 plant species. I want to know the determinants of the time that a pollinator needs to reach the next flower (Time; Dependent Variable). Therefore, I have lumped the 11 plant species, ran a backwise...
  17. L

    Is a 3-way ANOVA, an ANCOVA, or a linear regression best for my dataset?

    I've performed an experiment in which a cell line was treated with a cocktail of three different compounds (call them A, B, and C). Compound A was used at two concentrations, compound B was used at four concentrations, and concentration C was used at four concentrations. The goal was to see how...
  18. S

    Is normal dist OK for these count data?

    Hello, I am modelling some count data (ANCOVA). I use R for statistical computing. I am not sure if I must use a glm with poisson errors. There are 120 counts in 4 groups and only one zero count. The maximum count is 12. The median is about 4 and the distribution of...
  19. M

    df fot BETA t-test in ANCOVA

    Hi All, Perhaps this would be a silly question but, in ANCOV, what is the DF for t-test value for a covariate BETA coefficient calculated across all compared groups (i.e. beta like in a regression between covariate and DV but in ancova). Spss and Statistica give only t and p values but...
  20. P

    Which analysis should i use? Rgeression or ANOVA or any ....

    I am doing one analysis in Natural Science discipline: I have lots of data but know I don't know how can I analyze them. As I am not statistician: Could you please give an idea about what you think... See below the plan: 6xBlank (Control) Sampling purpose 1 Measures(GPD, VFA, NH4, N...