Re: [ccp4bb] How many reflections per shell for good statistics - data processing

2017-02-21 Thread Jorge Iulek
Dear Kay,     Thanks for your input.     My intention is to compare a number of datasets, to what resolution they extend to, based on a common criterion (which might be I>sig(I) or even CC1/2), but I think to make the comparison more

Re: [ccp4bb] How many reflections per shell for good statistics - data processing

2017-02-20 Thread Kay Diederichs
Hi Jorge, the answer probably depends to some extent on what you need the numbers for. The statistical error of the indicators is inversely proportional to the square root of the number of reflections. I seem to remember publications in the field of maximum likelihood refinement which report

[ccp4bb] How many reflections per shell for good statistics - data processing

2017-02-20 Thread Jorge Iulek
Dear all,     Is there any study to recommend the (minimum) number of reflections for adequate statistics in each shell during image processing? I mean, for indexes like R_meas or R_symm or CC1/2, it might be important to know the number of total