PPT Slide
2. Intensities and standard deviations
Scala compares the estimated standard deviation s(I) to the observed scatter, and tries to correct s(I) by a multiplication factor. This is done using a normal probability plot. A correction as a function of intensity is also done, but this is not yet automatic
s(I)’ = Sdfac * Sqrt [ s2(I) + (Sdadd * I)2 ]
The corrected s(I) is compared with the intensities: the most useful statistic is < <I>/ s(<I>) > (labelled Mn(I)/sd in table)
This statistic shows the improvement of the estimate of <I> with multiple measurements. It is the best indicator of the true resolution limit