interaction effects

  1. R

    Zero inflated negative binomial regression interpreting main and interaction effects

    I am running a zero inflated negative binomial model (zinb) and want to interpret the main and interaction effects. I have the following: People decide whether to purchase a good during a given week and I have their final purchase quantity (Min qty = 0 units and Max qty = 10 units observed...
  2. T

    One significant interaction out of many

    So I am in the process of interpreting a set of results. I conducted 6 regression analyses to determine if a variable acts as a moderator. One of the 6 interaction terms was significant. Should I attempt to rationalise this in terms of theory, or should I argue that the hypotheses were not met...
  3. R

    Compare differences between exp. and contr. of two groups

    Hi! I already used lots of search engines without finding an answer to my problem. I am testing two methods for manipulating religious belief. For each of the methods there exists an experimental and a control group. So there are in total four groups (between-subject design). My hypothesis...
  4. C

    Interactions in logistic regression - Please help

    Hi everyone, Currently I'm writing my thesis on the effects of divorce on children. It's a complex design so I guess I'll be posting more questions here :) My dependent variable is whether or not the respondent has ever been in a relationship. My independents are 2 dichotomous variables ...
  5. P

    Breaking-down main effect to examine demographic differences

    I showed videos of musical performances which where visually different, but the sound was identical. Participants graded both the appearance of the performer, and the quality of the musical performance. I got a statistically significant main effect of visual condition on audience ratings of...
  6. N


    Hello, I understand that multicollinearity is different from variable interactions. What I don't understand is whether an interaction of two variables can account for some of the common effects (multicollinearity) that contribute to the high R^2. I did not include variable interactions in...
  7. R

    Semipartial correlations for simple slopes

    Hello! I'm in need of some help for calculating sr2 for simple slopes. Here is my situation: I'm using SPSS. I have three IVs: x1: dichotomous and coded -1,1 x2: dichotomous and coded -1,1 x3: continuous centered variable I have a 3 way interaction that I've calculated the simple...
  8. J

    Meta-analysis - can I combine/use these studies?

    Hi! I'm trying to set up a meta-analysis with my thesis partner and we ran into trouble which our supervisor isn't able to solve. So I figured I'd turn to the internet :) Googling hasn't helped me much, so now I'm on a forum. In our research, we are looking for the effect of...
  9. R

    Implications of low standard deviation for a moderator

    Hello I have a model where Y = b0 +b1*X+ b2*Z +b3*XZ. Z is a moderator in my theory. In my data, Z is measured on a 5 point Likert type scale with mean = 3.27 and s.d. =.43. A reviewer wants to me to discuss the implications of what they consider "low" s.d. for the significance and...
  10. S

    AMMI algorythm

    Hi, Does anyone has experience using AMMI (additive main effects and multiplicative interactions)? If yes, could you please provide practical information on how it works and SAS code that performs the analysis? This is a technique used in multi-location, multi-year plant breeding...
  11. K

    Interaction effects, distributions not normal- is ANOVA justified??

    Hi! I have a 2*4*6 factorial design. the sample distributions in most cases are NOT normal (tested with Kolmogorov-Smirnof test). It is recommended to use non-parametric tests in such cases but my question is this: What test should I use to test for interaction effects? Thank you!
  12. K

    Interaction effects of nominal and ordinal variables on binary dependant variable

    Hi! I'm doing an analysis of interaction effects of one binary nominal variable (medication used), one ordinal variable (duration of therapy ; 1-few weeks, 2-less than 3 months, 4-less than six months, 5-more than six months) and one interval variable (age) on binary dependant variable (0- does...
  13. R

    Formerly non-significant main effect becomes significant after interaction is entered

    Hi there, I'm running a hierarchical regression with 3 IVs. First step: main effects, second step: two-ways, third step: three-ways. In the first two steps, one of the IVs was non-significant. Once the three-way interaction was entered in the third step (which was non-significant), the IV...