Insignificant correlation - significant regression


New Member
I couldn't find this on the search - maybe it's too basic ;)

So I have two variables which significantly positively correlate with each other (r = .35, p < .01). Both of these have insignificant correlations (p >.1) with a third variable (the first shows as weakly positive, the second as weakly negative).

However, on a regression analysis, together the first two predictors show up as significant predictors of the third variable. They both have significant standardised coefficients individually as well (I am using SPSS coefficient table here). However, one has a positive standardised coefficient (.26) and the other a roughly equal negative one (-.24).

I can see that this might have something to do with multicollinearity or suppressor effects, but I am a bit out of my depth at figuring out exactly what is going on? Could anyone explain in simple terms?


Omega Contributor
Plot scatterplots for each combination of three variables, than a 4th scatterplot with a x, y, z axis and see what the data pattern looks like.