mail[task #7180] Import of BRUKER Protein Dynamic Center Protject


Others Months | Index by Date | Thread Index
>>   [Date Prev] [Date Next] [Thread Prev] [Thread Next]

Header


Content

Posted by Edward d Auvergne on November 29, 2010 - 15:09:

Follow-up Comment #1, task #7180 (project relax):

The following file is a plot (and the script) of the distribution of error
estimates.  I am using a Gaussian centered at 20 with a standard deviation of
1.  I take 2 points (peak intensities from duplicated spectra) randomly from
the distribution and calculate the difference.  This is then repeated N times
(number of duplicated spectra) and the maximum difference is taken.  I repeat
this M times for determining some stats, where M = 1e6.  The average error
estimate is:

N = 2, ave(error) = 1.594
N = 3, ave(error) = 1.875
N = 4, ave(error) = 2.070
N = 5, ave(error) = 2.221
N = 6, ave(error) = 2.339
N = 100, ave(error) = 3.884

N = 2, sd(error) = 0.852
N = 3, sd(error) = 0.829
N = 4, sd(error) = 0.806
N = 5, sd(error) = 0.786
N = 6, sd(error) = 0.770
N = 100, sd(error) = 0.566


These are all log-normal distributions.  As you can see, the error estimate
is always on average overestimated, and the more duplicated spectra N, the
worse this becomes.  The spread of values is also a worry.  With 3 duplicated
spectra, the resultant errors are  1.875 +/- 0.829 which means that the error
estimates are all over the place.  The perfect estimate would be 1.000 +/-
0.000, as the sd is exactly 1.

(file #11436, file #11437, file #11438)
    _______________________________________________________

Additional Item Attachment:

File name: sampling_test.py               Size:1 KB
File name: sampling_test_good.agr         Size:8 KB
File name: sampling_test_good.ps          Size:15 KB


    _______________________________________________________

Reply to this item at:

  <http://gna.org/task/?7180>

_______________________________________________
  Message sent via/by Gna!
  http://gna.org/




Related Messages


Powered by MHonArc, Updated Mon Nov 29 15:20:17 2010