# interaction

1. ### Why is an interaction term better than two regressions?

I have struggled with the "because it is" and vague answers on this topic for a while and I was hoping someone could actually give a real reason why using an interaction term in regression is better than doing two regressions. For example: While doing a GLM to see how environmental factors...
2. ### Interaction of treatment with confounder

In a multivariate regression analysis, I examine the effect that a treatment method has on subjects' hemoglobin levels. Since this is a retrospective study, I could not control for gender (or age) by randomization prior to collection. As a result, I control for gender in my analyses. The...
3. ### moderation/mediation repeated measures

Hello everyone, I need help with interaction effects in multiple regression analysis. Study went like this: 120 participants solved 20 base-rate neglect tasks which all differed in ratio and congruence (mediators/moderators). They all solved statistical reasoning test (predictor). Correct...
4. ### MANCOVA with 2 dummy variables (Question about interaction probing)

Hello! I am running a MANCOVA with two dichotomous IVs and a 4 continuous DVs for my Master's thesis. When the first edits came back, I was asked to write about post-hoc probings of significant interactions. I am having a hard time understanding how one would "probe" these types of interaction...
5. ### Significant treatment*pretest interaction, but interaction not shown with regression lines

Hello, I have found that the interaction treatment by pretest is significant. However, the interaction is not depicted on the scatterplot (see attachments). Am I doing something wrong or can I say that the interaction is outside the range of possible test scores (0-10) and that the assumption...
6. ### 2x2 anova, no interaction

Hello, i want to compare male and female adults kinematics while normal walking and perturbation. I do 2x2 anova. The example graph is below. Both effects (gender and perturbation occurance) are significant but interaction is not. How can I get exact information where exactly are statistically...
7. ### Different main effect in MANOVA and two-way MANOVA? Which one do I use?

I did a MANOVA in SPSS and there is a significant main effect of the IV on only one of my two DVs. Then I did a two way ANOVA to include one more IV, but otherwise use the same variables I've used in the MANOVA (just entered one additional variable). However, suddenly the same IV that had a sig...
8. ### Should I use a MANOVA and then a two-way MANOVA or just the two-way MANOVA?

My research questions: - Is there an effect of the independent variable on the two dependent variables? - Is this effect of the independent variable on the two dependent variables stronger for females as opposed to males? I did a MANOVA for question 1 and it's significant. I did a two-way...
9. ### Interpretation of interaction terms in a multiple linear regression

I try to improve my statistical knowledge and right now I am working on a regression that contains interaction terms. I am currently investigating the effects of different variables (a1, a2 etc.) on the quantity of chairs sold in a transaction (dependent variable). To see if effects are...
10. ### IVs and moderator variables correlate in three-way interaction - problematic?

Hi everybody, let's assume I hypothesize: H1: A direct effect of X1 on Y H2: A direct effect of X2 on Y H3: A two-way interaction between X1 and X2 H4: A three-way interaction between X1, X2 and X3 H5: A three-way interaction between X1, X2 and X4 and run the following OLS regressions to test...
11. ### Interaction

Hi, In your opinion is this a multiplicative qualitative or quantitative interaction?
12. ### Significant interaction no significant comparision

Dear community, I did a linear mixed model full factorial with 2x2. I use the linear mixed model like an ANOVA and I have one significant main effect and a significant interaction effect.To solve the interaction I split my data by one variable and analyze the main effect by the other variable...
13. ### Multinomial Logistic Regression, 2x2 Between Participants Design

Hello everyone, I would really appreciate some advice on how to interpret my SPSS-Output. I have tried to figure it out myself, but haven't been able to get an answer. I have 2 binary independent variables and 1 dependent variable with 3 categorical outcomes. So a 2x2 Design. In order to...
14. ### high correlation among interaction terms

Y= alpha+ b1*x1 + b2*x2 + b3* x3 +b4*x4 + b5*dummy1*x1+b6*dummy1*x2 + b7*dummy1*x3 +b8*dummy1*x4 I run the correlation between all the regression variables and I found that all variables that are multiplied by dummy1 are highly correlated (correlation can reach up to 0.77). is this normal...
15. ### Interaction in simple Repeated Measures Anova

Dear all, I am currently struggling with my masters-thesis on the subject of control variables or covariates in a repeated measures analysis. I have a rather strait-forward 2x2 data-matrix: 2 dichotomous independent variables. (I will call them condition & treatment) 1 dependent...
16. ### Question about 3X3 repeated measures ANOVA and simple effects

First time posting here. I have conducted a transcranial magnetic stimulation study and am analyzing the results as a 3x3 repeated measures ANOVA. I'm a grad student in cognitive psychology. 1. purpose of the study: to dissociate language from other forms of cognition using TMS. 2...
17. ### Factorial Design

Suppose a dermatologist wants to study the effectiveness of two different preparations of a skin lotion using two different forms of application (for example, one vs. two applications per day). He has available 12 patients with a certain skin disease and he can apply one form of medication (that...
18. ### How do i analyse interaction in 3x2 ANOVA in SPSS

Hi, i've discovered a significant interaction in my 3x2 ANOVA in my psychology dissertation (3x2 Between Subjects Design, using SPSS). I was wondering which post-hoc analysis i should use to study this interaction. My tutor has provided us with example instructions, which involve splitting the...
19. ### Interpreting strange results

So effectively I have two variables, language problems, and emotional problems, both of which independently cause an increase in a third variable, which is behaviour problems. I hypothesized that high emotional problems would significantly moderate the relationship between language problems and...
20. ### 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...