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From |
"Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu> |

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

Subject |
RE: st: Wald interval and the WSJ |

Date |
Thu, 14 Aug 2008 09:28:31 -0700 |

Using the data from the paper (same as Maarten's) I got . tabi 102 872\69 793,row | col row | 1 2 | Total -----------+----------------------+---------- 1 | 102 872 | 974 | 10.47 89.53 | 100.00 -----------+----------------------+---------- 2 | 69 793 | 862 | 8.00 92.00 | 100.00 -----------+----------------------+---------- Total | 171 1,665 | 1,836 | 9.31 90.69 | 100.00 Upper bound of two-sided confidence interval . disp (.1047-.08)+1.96*sqrt(.1047*(1-.1047)/974+.08*.92/862) .05111444 Non-inferiority test . disp (.1047-.08-.03)/sqrt(.1047*(1-.1047)/974+.08*.92/862) -.39326968 I don't seem to be able to reproduce the z needed for a p of 0.0484... Tony Peter A. Lachenbruch Department of Public Health Oregon State University Corvallis, OR 97330 Phone: 541-737-3832 FAX: 541-737-4001 -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Maarten buis Sent: Thursday, August 14, 2008 8:09 AM To: statalist@hsphsun2.harvard.edu Subject: Re: st: Wald interval and the WSJ --- David Airey <david.airey@Vanderbilt.Edu> wrote: > And also the article doesn't emphasize effect size, which might make > the quibbling over p values moot too. Actually, the point estimate seems to suggest that the new stent does better then the old one, if I read the original article (http://content.onlinejacc.org/cgi/content/full/49/16/1676) correctly, and I know absolutely nothing about cardiology other than that a working hart is sorta crucial in staying alive. I read this article as follows: The thing under study is how well two types of stents prevent a thing called TVR (target vessel revascularization) which is apperently a bad thing. In the group with old stents this occured 68 times out of 855 (7.95%), while in the group with new stents this occured 67 out of 956 times (7.01%). The purpose of this study is to test the hypothesis that the proportion new - porportion old > .03 . I have been looking around if I could reproduce the tests reported in the Wall Street Journal using Stata, but remained unsuccesful. This probably says more about me than about Stata, because statistically this is also unfamiliar terain for me, as I almost always do some sort of regression, moreover if I where to look at tests like these I would probably prefer odds ratios rather than risk differences. -- Maarten ----------------------------------------- Maarten L. Buis Department of Social Research Methodology Vrije Universiteit Amsterdam Boelelaan 1081 1081 HV Amsterdam The Netherlands visiting address: Buitenveldertselaan 3 (Metropolitan), room Z434 +31 20 5986715 http://home.fsw.vu.nl/m.buis/ ----------------------------------------- Send instant messages to your online friends http://uk.messenger.yahoo.com * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/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/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**Re: st: Wald interval and the WSJ***From:*David Airey <david.airey@Vanderbilt.Edu>

**Re: st: Wald interval and the WSJ***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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