1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Normally distributed data?

  1. Sep 12, 2011 #1
    1. The problem statement, all variables and given/known data
    Suppose I have a set of measurements of a quantity Q, where the resolution R is the same for all data di. However, R is unknown, and I wish to find it.

    In my book they do this by writing the likelihood L (or rather, ln(L)) as the Gaussian, so

    \ln L = \sum\limits_i { - \ln R_i \sqrt {2\pi } } - \sum\limits_i {\frac{{\left( {d_i - Q } \right)^2 }}{{2R_i }}}

    Now they differentiate wrt. the mean Q and the deviation Ri = R, yielding two equations. Solving these yields

    R^2 = \frac{1}{N}\sum\limits_i {\left( {d_i - Q} \right)^2 }

    This is the standard result we are "used" to. But does this mean that every single time I use this formula on a set of data, then I am implicitly assuming that the data is normally distributed?

    Last edited: Sep 12, 2011
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted