Thanks Ian. e On 12 March 2017 at 21:56, Ian Tickle <ianj...@gmail.com> wrote:
> > Eleanor, > > Phil is right about the bias of the weighted mean, here's how I do it > using a minimum mean-squared error estimator which seems to give more > accurate results than either the unweighted or the weighted mean: > > http://staraniso.globalphasing.org/Optimal-F-estimator.pdf > > This is actually about Fmean but the same applies to Imean. > > This actually only makes a significant difference to the result if there's > a big difference between sd(I+) and sd(I-), which is obviously not very > common. > > 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 >>> >> >> >
