Converting Error in Log2 Form for Arbitrary Base

[dipluso]

Hi,

I am trying to represent my data in log2 form rather than "fold change" and I am embarrassed to say I can't remember how convert the error.

For example, I have x=3.96 (mean), deltax=0.28 (standard dev).

Thus, log2(x)=0.598.

But how do I convert the error??

I know how to do it for log10: 0.434(deltax/x) but I can't for the life of me remember how to derive it for an arbitrary base.

Any help/pointers much appreciated.

Thanks!

 

[dipluso]

Duh, figured it out.

For y=ln(x), error dy=dx/x

since lob(x) base b = ln(x)/ln(b)

Then for y=lob(x) base b , error is dy=(1/ln(2))(deltax/x)

Done. Cheers, -Alex