spss做logistic回归，说无法计算协方差矩阵，求教大神们！！！

hplcdadong 发表于 2013-3-30 22:52
Perform univariate analysis before logistic regression to check if some of your variables have "comp ...

这个大神在说清楚点的嘛。。。 如果存在你说的那种情况怎么办啊。 我自己用可靠性分析计算协方差矩阵，项间协方差矩阵是可以计算出来的。 能不能帮帮我啊！！大神！！！ 要挂了！！

Don't know the detail of your model, it seems that the following should be helpful.

Before you do any logistic regression, the following are two basic things to check:
1)missing value pattern of your dependent and independent variables since logistic regression use listwise deletion of observation values if any of your variables have missing values
2)perform univariate analysis between your dependent and independent variables to
      a) have a general idea which independent variables should be in the final model
      b) check if some of your independent variable have "complete separation" for dependent variable (an example: assume "death" is your outcome, you find all death are male)

hplcdadong 发表于 2013-3-31 07:16
Don't know the detail of your model, it seems that the following should be helpful.

Before you do ...

谢谢你的回复，非常感谢。有点看的不是很明白。。 能不能说汉语的，我英语比较差看的不是很明白。是不是要先检查数据的是否完整。然后最后的模型需要一个独立的变量。 但是独立变量又不能完全分离的？是不是这个意思啊？ 我能不能把数据发给你，你帮我看看啊！万分感激！！！

hplcdadong 发表于 2013-3-31 07:16
Don't know the detail of your model, it seems that the following should be helpful.

Before you do ...

大神，再给我指点一下嘛，那个软件计算出来说，无法计算参数协方差矩阵。再给我指点一下嘛。。。。

hplcdadong 发表于 2013-3-31 07:16
Don't know the detail of your model, it seems that the following should be helpful.

Before you do ...

在不在啊，你来帮帮我啊。。。。求你了。

The following is an excellent example for your condition (you'll get the same error message when you run logistic regresson on the following data)

Consider the following data

y x z
1 1 1
1 2 2
1 3 3
1 4 4
1 5 5
0 6 5
0 7 6
0 8 6
0 9 7
0 9 8

Consider X as a single predictor of Y. There is a situation
in these data called separability. Note that a cutpoint on
X of 5.5 separates the Ys. Try a logistic regression of
Y on X, and you get Bs and Standard errors that blow up.
Likewise, consider Z as a single predictor. Here, Z=5
straddles the boundary of Y being 0 or 1. A similar thing
happens with Z as a single predictor.

X and Z are highly but not perfectly correlated. When you
do a logistic regression of Y on both X and Z, Logistic Regression prints
the kind of messages that you report.

So, take a closer look at your data, and look for situations
of separability or near-separability (complete or near-complete separation) and/or high correlation
in your predictors.

hplcdadong 发表于 2013-4-2 22:53
The following is an excellent example for your condition (you'll get the same error message when you ...

非常非常感谢你这么详细的解答。 能不能在问一下，你说的这种情况，用什么方法能检查出来吗？怎么检查啊？ 谢谢你。

Actually, the last example I presented have given you answer.

Anyway,
1)as regards to "complete/near-complete separation", run univariate logistic regression between your dependent variable and each of your independent variable, your will see very large "S.E" (blowing up standard error) in "Variables in the Equation" in SPSS output if there is "complete/near-complete separation"
2)as regards to high correlation (multicolliniarity), for continuous variable, just run correlation matrix of all your independent variables  to have a general idea of their correlation

Good luck

hplcdadong 发表于 2013-4-5 03:55
Actually, the last example I presented have given you answer.

Anyway,

Thanks very much!!! The problem has been solved,thank you again. You are a good man,best wishes to you!!!

请问楼主 这个问题后来是怎么解决的呢 和你遇到了相同的问题 急求