Nov 19th, 2008| 01:34 am | Posted by hlee

There will be a special session at the 213th AAS meeting on **meaning from surveys and population studies (SPS)**. Until then, it might be useful to pull out some interesting and relevant papers and questions/challenges as a preliminary to the meeting. I will not list astronomical catalogs and surveys only, which are literally countless these days but will bring out some if they change the way how science is performed with a description of the catalog (the best example would be SDSS, Sloan Digital Sky Survey, to my knowledge). Continue reading ‘[SPS] Testing Completeness’ »

Tags:

completeness,

incompleteness,

normal,

SPS,

test Category:

arXiv,

Astro,

Cross-Cultural,

Frequentist,

Methods,

News,

Quotes,

Stat,

Uncertainty |

Comment
Jul 1st, 2008| 10:10 pm | Posted by hlee

If getting the first derivative (score function) and the second derivative (empirical Fisher information) of a (pseudo) likelihood function is feasible and checking regularity conditions is viable, a test for global maximum (Li and Jiang, JASA, 1999, Vol. 94, pp. 847-854) seems to be a useful reference for verifying the best fit solution. Continue reading ‘A test for global maximum’ »

Jun 19th, 2008| 11:42 pm | Posted by hlee

I was questioned by two attendees, acquainted before the AAS, if I can suggest them clustering methods relevant to their projects. After all, we spent quite a time to clarify the term **clustering.** Continue reading ‘my first AAS. IV. clustering’ »

Jan 11th, 2008| 03:44 pm | Posted by hlee

It is notable that there’s an astronomy paper contains **AIC, BIC**, and **Bayesian evidence** in the title. The topic of the paper, unexceptionally, is cosmology like other astronomy papers discussed these (statistical) information criteria (I only found a couple of papers on model selection applied to astronomical data analysis without articulating CMB stuffs. Note that I exclude Bayes factor for the model selection purpose).

To find the paper or other interesting ones, click Continue reading ‘[ArXiv] 2nd week, Jan. 2007’ »

Tags:

AIC,

Bayesian evidence,

BIC,

catalog,

Classification,

CMB,

confidence interval,

consistency,

correlation,

GRB,

information criterion,

Model Selection,

SDSS,

test,

WMAP Category:

arXiv |

Comment
Jul 12th, 2007| 12:02 am | Posted by hlee

Since I start reading arxiv/astro-ph abstracts and a few relevant papers about a month ago, so often I see chi-square something as an optimization or statistical inference tool. Chi-square function, chi-square statistics, chi-square goodness-of-fit test are the words that serve different data analysis purposes but under the same prefix. As a newbie to statistics, although I learned chi-square distribution and chi-square test, doing statistics with chi-square are somewhat considered to be obsolete in terms of robust applications to modern data. These are introduced as one of many distributions and statistical tests. Nothing special. However, in astronomy, chi-square becomes the almost only method for statistical data analysis. I wonder how such strong bond between chi-square tactics and astronomer’s keen mind to data analysis has happened?

Continue reading ‘What is so special about chi square in astronomy?’ »