Page 1 of 1

CMB data help

Posted: February 08 2008
by Zhao Wen
Dear friends:
Who can explain the meaning of binned data of CMB power spectra? How to get the binned data (mean value and the error bar) from the unbinned data? or introduce a paper for me? Thanks a lot!

CMB data help

Posted: February 08 2008
by Sarah Bridle
I thought the binned data was just the weighted mean of the unbinned data (with the weighted mean error bar)? It certainly makes for a sensible looking plot..

Re: CMB data help

Posted: February 08 2008
by Zhao Wen
Thank you very much! But, as we known, in the bined data, the error bar is much smaller than the unbined data. If is only the weighted mean, the error bar of binned data can not be obtained.
Sarah Bridle wrote:I thought the binned data was just the weighted mean of the unbinned data (with the weighted mean error bar)? It certainly makes for a sensible looking plot..

Re: CMB data help

Posted: February 09 2008
by Anze Slosar
Zhao Wen wrote:Thank you very much! But, as we known, in the bined data, the error bar is much smaller than the unbined data. If is only the weighted mean, the error bar of binned data can not be obtained.
Sarah Bridle wrote:I thought the binned data was just the weighted mean of the unbinned data (with the weighted mean error bar)? It certainly makes for a sensible looking plot..
If you add 1/\sigma^2 it should probably be good enough for most purposes...., i.e. 1/\sigma_binned^2 = \sum 1/\sigma_i^2

Re: CMB data help

Posted: February 13 2008
by Zhao Wen
Thank you very much! I have known it!


Anze Slosar wrote:
Zhao Wen wrote:Thank you very much! But, as we known, in the bined data, the error bar is much smaller than the unbined data. If is only the weighted mean, the error bar of binned data can not be obtained.
Sarah Bridle wrote:I thought the binned data was just the weighted mean of the unbinned data (with the weighted mean error bar)? It certainly makes for a sensible looking plot..
If you add 1/\sigma^2 it should probably be good enough for most purposes...., i.e. 1/\sigma_binned^2 = \sum 1/\sigma_i^2