Suppressor variables are commonly defined as variables that are correlated with another predictor & causally unrelated to the response, but that are nonetheless significant in a multiple regression model & enhance the significance, magnitude of effect, or predictive value of the other variable.

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How can including an IV uncorrelated with the DV improve a multiple regression model?

Let's say $Y$ is my DV, and $X_1$,and $X_2$ are IVs: \begin{align} \newcommand{\Cor}{\rm Cor} \Cor(Y,X_1) &= 0.7994172 \\ \Cor(Y,X_2) &= -0.00041 \\ \Cor(X_1,X_2) &= 0.505 ...
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ANCOVA Supressor effect?

I'm having a wierd kind of effect I don't fully understand when running an ANCOVA analysis. To keep it simple I have a variable X and a variable Y, these variables are significantly correlated to ...
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Suppression effect in regression: definition and visual explanation/depiction

What is a suppressor variable in multiple regression and what might be the ways to display suppression effect visually (its mechanics or its evidence in results)? I'd like to invite everybody who has ...
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648 views

How to tell if my variable is a suppressor?

I am analyzing data using path analysis and I am hoping someone here can help. In my model, I am looking at predictors of a variable, $Y$. In the path model, $Y$ has 4 significant predictors lets ...
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How can adding a 2nd IV make the 1st IV significant?

I have what is probably a simple question, but it is baffling me right now, so I am hoping you can help me out. I have a least squares regression model, with one independent variable and one ...
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441 views

Interpreting Omitted Variables

I do not fully understand how to interpret the difference between two statistical models where they only differ based on whether a certain variable is included on the right hand side. If the results ...
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How to interpret a predictor with a positive structure coefficient and a negative standardised coefficient in discriminant function analysis?

I am doing a discriminant function analysis and I have four continous independent variables and one categorical dependent variable (that has 3 groups). I have chosen to do this analysis to see how ...
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137 views

Differences in coefficients

Suppose I want to see whether $z$ is a confounder for a model with $y$ the outcome variable and $x$ the predictor. If I adjust for $z$, and the adjusted coefficient of $x$ changes versus the ...