|
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]
st: dealing with 0 in cells in 2x2 tables
Hello All, my first post so be honest if you feel this type of question
is not suitable for this forum - any help gratefully received.
I am building a logistic regression model but first I wish to carry out
bivarite analyses measuring the effect of each exposure on the outcome.
In my 2 by 2 table I have 0 in one cell so the odds ratio is either
infinity of 0. However, the chi square test shows that the exposure
(homelessness) is significantly associated with the outcome, so I cannot
simply ignore this variable in my bivarite and multivariate analyses.
How do people deal with this situation?
Thanks,
Caryl
tabodds spoonB_vis_writ homeless2
------------------------------------------------------------------------
--
homeless2 | cases controls odds [95% Conf.
Interval]
------------+-----------------------------------------------------------
--
No | 0 22 0.00000 .
.
Yes | 22 119 0.18487 0.11731
0.29135
------------------------------------------------------------------------
--
Test of homogeneity (equal odds): chi2(1) = 3.94
Pr>chi2 = 0.0470
Score test for trend of odds: chi2(1) = 3.94
Pr>chi2 = 0.0470
. mhodds spoonB_vis_writ homeless2
Maximum likelihood estimate of the odds ratio
Comparing homeless2==1 vs. homeless2==0
----------------------------------------------------------------
Odds Ratio chi2(1) P>chi2 [95% Conf. Interval]
----------------------------------------------------------------
. 3.94 0.0470 . .
----------------------------------------------------------------
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/