Using sperman correlations, I've found that A/B (A divided by B) is significantly

correlated with C. A by itself does not correlate significantly with C, neither does B correlate significantly with C by itself.

(Of note A*B does not correlate with C using Spearman's rho.)

Because of my finding of A/B correlating with C, I suspect that there is an interaction

effect going on. I wonder how I should investigate if this is the case in a meningful way.

My hypothesis - which would fit nicely with previous research and studies - is that higher values of A, combined with lower values of B (thereby creating a higher A/B fraction) interact so that A/B correlates positively with C.

I have tried visualizing and examining this using all sorts of plots and/or calculations, and it

*seems*like my hypothesis holds - but I need help finding a way to calculate or visualize this that would be statistically sound, so that it actually could be published in an article.

All help appriciated!