efficiency calculation from non-10 fold dilutions - (Oct/14/2011 )

I have done a 5 fold dilution series with 6 points because my genes of interest are relatively low copy number and I wanted to get enough points in my dilution series to feel confident using these primers.

I am not clear how to calculate the efficiency from log base 5. My R2 values are nearly perfect (better than .998) and my slopes are around 1.4.

I thought I should use this calculation 5^(-1/m)...but the numbers I get don't seem right.

if E=10^(-1/m), how does this change for non-10 fold dilution series?

Thanks

FWIW, I think my efficiencies are way off...or I'm calculating my slope wrong. My slope should be close to x where 2^x=5 or 2.322. which 5^(-1//2.322) = 2. So nevermind.