我在用sas做配对logistic回归时遇到了一些问题,sas给的提示看不明白所以不知道哪里出问题了,还请大家帮忙看一下,十分感谢!
这是我的语句,是从一本书上看到的,具体原理我也不清楚,因为因变量是某事件的发生数,所以使用了freq(?):
proc logistic data=prin descending;
freq dno10;
class type/param=ref descending;
model y=type;
strata stratum2;
run;
然后日志给出了这些warning:
4 proc logistic data=prin descending;
5 freq dno10;
6 class type/param=ref descending;
7 model y=type;
8 strata stratum2;
9 run;
NOTE: PROC LOGISTIC is modeling the probability that y=1.
WARNING: NRRIDG Optimization cannot be completed.
NOTE: NRRIDG needs more than 25 iterations or 250 function calls.
WARNING: Convergence was not attained in 25 iterations. You may want to increase the maximum number of iterations
(MAXITER= option) or change the convergence criteria (ABSFCONV=, FCONV=, GCONV=, XCONV= options) in the MODEL
statement.
WARNING: The LOGISTIC procedure continues in spite of the above warning. Results shown are based on the last maximum
likelihood iteration. Validity of the model fit is questionable.
NOTE: 从数据集 WORK.PRIN 读取了 36 个观测。
NOTE: “PROCEDURE LOGISTIC”所用时间(总处理时间):
实际时间 3.15 秒
CPU 时间 3.04 秒
然后结果中的OR值非常奇怪:
Odds Ratio Estimates
Point 95% Wald
Effect Estimate Confidence Limits
type 6 vs 0 >999.999 <0.001 >999.999
type 5 vs 0 >999.999 <0.001 >999.999
type 2 vs 0 >999.999 <0.001 >999.999
请大家帮忙看一下是语句出了问题还是我的数据有问题,谢谢!