Re: [ccp4bb] detection of anomalous signal using HKL2000

2010-06-29 Thread Felix Frolow
Quoting "Phil Evans" : Can anyone explain what Zbyszek Otwinowski means by Chi squared? If I understand properly, CHI**2 value as used in Scalepack is: SUM(-Ij)**2/SUMsigma(I)**2 (I have to use formula editor to write it properly, but the idea is clear) and is useful in exhibiting and det

Re: [ccp4bb] detection of anomalous signal using HKL2000

2010-06-29 Thread Phil Evans
Can anyone explain what Zbyszek Otwinowski means by Chi squared? I can't find a definition in any of his papers (though I may have missed it). Is there a reference? It doesn't seem obviously related to the chi squared distribution ("In probability theory and statistics, the chi-square distribut