http://spssx-discussion.165.s1.nabble.com/logistic-regression-question-tp5047539p5049811.html
Sorry, I don't see the original post - I don't have any comment on Lori's
reply, but I can address the original question. I have aligned the chart
(as my mail displays it) to show that all the individual were classified as "1".
Okay, you have a classification equation; you have an arbitrary cut-off
score that labels subjects into one group or the other. Seeing the cutoff
place everyone in the same group is more common when the groups are
proportionately 90/10 instead of 74/26, but this shows it can happen here, too.
- Look at the actual classification scores, and draw your own line
where it makes the fraction of errors about the same in either
direction.
--
Rich Ulrich
Date: Sun, 4 Dec 2011 18:06:48 -0800
From:
[hidden email]Subject: Re: logistic regression question
To:
[hidden email]Exp(1.471) = 4.35, that is your odds ratio
Is your independent variable categorical?
If not, a one unit increase in your IV would yield a 335% greater chance of membership in the "1" value of your DV.
If it is categorical, members of the IV group at the "1" level have a 335% greater chance of membership in the "1" value of the DV.
Lori
On Sun, Dec 4, 2011 at 7:49 PM, Jordan Kennedy [via SPSSX Discussion]
<[hidden email]> wrote:
Hello all:
I have run a simple bivariate logistic regression SPSS 19 for Windows.
The predictor is significantly associated with the outcome--with a
fairly large Odds Ratio. However, the classification table listed does
not classify particularly well. I have pasted the output below. Any
help would be greatly appreciated.
Classification Table(a)
Predicted
o_adhdalc
Observed .00 1.00 Percentage Correct
Step 1 o_adhdalc .00 209 0 100.0
1.00 74 0 .0
Overall Percentage 73.9
Variables in the Equation
B S.E. Wald df Sig. Exp(B)
Step 1a p2_alcadhd_l 1.471 .298 24.377 1 .000
Constant -3.335 .512 42.450 1 .000 .036
Thank you!
[...]