Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
Nick Cox <njcoxstata@gmail.com> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: higher occurrence of disease X in rare disease Y |

Date |
Thu, 5 Dec 2013 18:54:34 +0000 |

Say rather that C (largely for Stata) and S (marginally for Stata) are part of the shared heritage. Nick njcoxstata@gmail.com On 5 December 2013 18:16, Doug Hemken <dehemken@wisc.edu> wrote: > Thanks, Nick. I see Mata is more R-like than I had appreciated! > > On 12/05/13, Nick Cox wrote: >> Doug's code is fine and suits the purpose perfectly. >> >> A footnote is to underline that Mata can be used to the same "smart >> calculator" end, e.g. >> >> . mata >> : X = (0..6)' >> : binomialp(6,X,1/36) >> 1 >> +---------------+ >> 1 | .8444875698 | >> 2 | .1447692977 | >> 3 | .0103406641 | >> 4 | .0003939301 | >> 5 | 8.44136e-06 | >> 6 | 9.64727e-08 | >> 7 | 4.59394e-10 | >> +---------------+ >> : binomialp(6,(0..6)',1/36) >> 1 >> +---------------+ >> 1 | .8444875698 | >> 2 | .1447692977 | >> 3 | .0103406641 | >> 4 | .0003939301 | >> 5 | 8.44136e-06 | >> 6 | 9.64727e-08 | >> 7 | 4.59394e-10 | >> +---------------+ >> >> >> Nick >> njcoxstata@gmail.com >> >> >> On 5 December 2013 14:42, Doug Hemken <dehemken@wisc.edu> wrote: >> > Here is a script that illustrates the probabilities using Stata, it is such a small problem that you can illustrate statistical power by trail-and-error: >> > >> > set obs 7 >> > gen X = _n - 1 >> > gen prob = binomialp(6,X,1/36) >> > gen prob10 = binomialp(10,X,1/36) >> > gen prob12 = binomialp(12,2*X,1/36) >> > >> > >> > On 12/05/13, Doug Hemken wrote: >> >> If your sample size is literally six cases, then your unconditional probability of seeing disease X is 0.145. If there is no relation between Y and X, it wouldn't be too unusual to see 1 case of X crop up in 6 cases of Y. This is from a binomial distribution. >> >> >> >> On 12/05/13, "tiong21@netzero.net" wrote: >> >> > The prevalence of disease (X) is 1 in 36 in the general population. In a sample population with a very rare disease (Y) of unknown etiology, the prevalence of disease X is 1 in 6 ( ie: 1 case of X was found in the sample population of 6 rare cases of disease Y. How do I show statistically that this higher occurrence of disease X in rare disease Y is not due to chance? And as a corollary suggest that disease X may be a contributory factor in the etiology of disease Y (an issue of causality). Furthermore, should a Poisson distribution be used to calculate the probabilities? A sample Stata script will be much appreciated. >> >> > >> >> > >> >> > Tiong The >> >> > tiong21@netzero.net >> >> > >> >> > * >> >> > * For searches and help try: >> >> > * http://www.stata.com/help.cgi?search >> >> > * http://www.stata.com/support/faqs/resources/statalist-faq/ >> >> > * http://www.ats.ucla.edu/stat/stata/ >> >> >> >> -- >> >> Doug Hemken >> >> 4226I Social Science Bldg. >> >> >> >> dehemken@wisc.edu >> >> 262-4327 >> >> * >> >> * For searches and help try: >> >> * http://www.stata.com/help.cgi?search >> >> * http://www.stata.com/support/faqs/resources/statalist-faq/ >> >> * http://www.ats.ucla.edu/stat/stata/ >> > >> > -- >> > Doug Hemken >> > 4226I Social Science Bldg. >> > >> > dehemken@wisc.edu >> > 262-4327 >> > >> > To make a consulting appointment send me an email, or use the on-line scheduler: >> > https://calendar.wisc.edu/scheduling-assistant/public/profiles/PlRxCykH.html >> > * >> > * For searches and help try: >> > * http://www.stata.com/help.cgi?search >> > * http://www.stata.com/support/faqs/resources/statalist-faq/ >> > * http://www.ats.ucla.edu/stat/stata/ >> >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/faqs/resources/statalist-faq/ >> * http://www.ats.ucla.edu/stat/stata/ > > -- > Doug Hemken > 4226I Social Science Bldg. > > dehemken@wisc.edu > 262-4327 > > To make a consulting appointment send me an email, or use the on-line scheduler: > https://calendar.wisc.edu/scheduling-assistant/public/profiles/PlRxCykH.html > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**References**:**st: higher occurrence of disease X in rare disease Y***From:*"tiong21@netzero.net" <tiong21@netzero.net>

**Re: st: higher occurrence of disease X in rare disease Y***From:*Doug Hemken <dehemken@wisc.edu>

**Re: st: higher occurrence of disease X in rare disease Y***From:*Doug Hemken <dehemken@wisc.edu>

**Re: st: higher occurrence of disease X in rare disease Y***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: higher occurrence of disease X in rare disease Y***From:*Doug Hemken <dehemken@wisc.edu>

- Prev by Date:
**Re: st: How to calculate weighted mean** - Next by Date:
**Re: st: RE: Comparing 2 proportions with Stata** - Previous by thread:
**Re: st: higher occurrence of disease X in rare disease Y** - Next by thread:
**st: Online course: Regression Models as a Tool in Medical Research 2014** - Index(es):