Eleanor I notice that you are calculating a weighted mean using 1/sd(I) as the weight whereas in least squares one would of course normally use variance-weighting, i.e. 1/sd(I)^2. I assume this is intentional and is a way to reduce the bias effect of weighting, so that the resulting bias of the mean would be intermediate between that of an unweighted and a variance-weighted mean, though the variance of the mean would no longer be a minimum.
Assuming that it was indeed intentional, I will see if I can find the program I used to simulate the various ways of calculating the mean using the MSE as the measure of accuracy and see how this method compares with the others. Cheers -- Ian On 12 March 2017 at 17:58, Eleanor Dodson <eleanor.dod...@york.ac.uk> wrote: > You read: > h k l IPLUS SIGIPLUS INEG SIGINEG > Then program calculates this: > > SIGIMEAN = SIGIPLUS*SIGINEG/(SIGIPLUS+SIGINEG) > > IMEAN = (IPLUS/SIGIPLUS + INEG/SIGINEG)*SIGIMEAN > > ie: IMEAN = ( IPLUS*SIGINEG + INEG * SIGIPLUS ) / /(SIGIPLUS+SIGINEG) > > Is that the right thing to do? Not sure! > > Eleanor Dodson > > > > On 11 March 2017 at 15:18, Karthikeyan Subramanian <skarthi...@gmail.com> > wrote: > >> Dear CCP4bb, >> >> How IMEAN and SIGIMEAN is calculated in scalepack2mtz if the input is >> with anomalous intensity (obtained from HKL2000). Any guide/reference is >> highly appreciated. >> >> Thanks in advance, >> >> With regards >> >> Karthikeyan S. >> >> Principal Scientist >> >> IMTECH, Chandigarh >> > >
