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 |
Doug Hemken <dehemken@wisc.edu> |

To |
statalist@hsphsun2.harvard.edu |

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

Date |
Thu, 05 Dec 2013 12:16:28 -0600 |

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/

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

**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>

- Prev by Date:
**Re: st: How to calculate weighted mean** - Next by Date:
**Re: st: How to calculate weighted mean** - Previous by thread:
**Re: st: higher occurrence of disease X in rare disease Y** - Next by thread:
**Re: st: higher occurrence of disease X in rare disease Y** - Index(es):