1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Error propagation log base 2

  1. Jun 6, 2009 #1

    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.

    Last edited: Jun 6, 2009
  2. jcsd
  3. Jun 6, 2009 #2
    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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook