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/