# I need help back-calculating a correlation coefficient for a meta analysis!

• Mar 21st 2012, 05:13 AM
I need help back-calculating a correlation coefficient for a meta analysis!
Hi everyone,
I have never posted on this board before, so please bear with me if I am noob-ish. Also, sorry for cross-posting, since I accidentally posted this in the high school forum a second ago!

I am doing a meta-analysis on plant physiology studies, using the correlation coefficients from studies that regressed plant traits against altitude. However, some give the response variable as SLA (specific leaf area, units m^2 g^-1) and others give it as LMA (leaf mass per area, units g m^-2).

SLA = 1/LMA

I want to convert to LMA, but many published studies do not include all the raw data. Usually they include some combination of the r^2, r, and/or b1 (regression slope) values.

So my question is, if you have the correlation coefficient r between two variables x and y, can you use that information alone to calculate r for x and 1/y? If not, what other information do you need?

Thanks so much for your help!

-Quentin @ Univ of Tennessee