如何在SAS中进行逻辑回归预测概率? [英] How to predict probability in logistic regression in SAS?

问题描述

我对SAS非常陌生，并尝试使用SAS中的逻辑回归来预测概率.我从SAS支持网站获得以下代码:

I am very new to SAS and trying to predict probabilities using logistic regression in SAS. I got the code below from SAS Support web site:

  data vaso;
  length Response $12;
  input Volume Rate Response @@;
  LogVolume=log(Volume);
  LogRate=log(Rate);
  datalines;
3.70  0.825  constrict       3.50  1.09   constrict
1.25  2.50   constrict       0.75  1.50   constrict
0.80  3.20   constrict       0.70  3.50   constrict
0.60  0.75   no_constrict    1.10  1.70   no_constrict
0.90  0.75   no_constrict    0.90  0.45   no_constrict
0.80  0.57   no_constrict    0.55  2.75   no_constrict
0.60  3.00   no_constrict    1.40  2.33   constrict
0.75  3.75   constrict       2.30  1.64   constrict
3.20  1.60   constrict       0.85  1.415  constrict
1.70  1.06   no_constrict    1.80  1.80   constrict
0.40  2.00   no_constrict    0.95  1.36   no_constrict
1.35  1.35   no_constrict    1.50  1.36   no_constrict
1.60  1.78   constrict       0.60  1.50   no_constrict
1.80  1.50   constrict       0.95  1.90   no_constrict
1.90  0.95   constrict       1.60  0.40   no_constrict
2.70  0.75   constrict       2.35  0.03   no_constrict
1.10  1.83   no_constrict    1.10  2.20   constrict
1.20  2.00   constrict       0.80  3.33   constrict
0.95  1.90   no_constrict    0.75  1.90   no_constrict
1.30  1.625  constrict
;
ods graphics on;

proc logistic data=vaso PLOTS = (ROC EFFECT);
  model Response(event='constrict')=LogRate LogVolume 
  /ctable pprob=0.5 selection=forward rsquare link=logit expb ;
run;
ods graphics off; 

我想知道当我有logVolume= 1.5和logRate=1.3时如何预测概率.另外，您能解释一下length Response $12的意思吗?

I am wondering how I could predict the probability when I have logVolume= 1.5 and logRate=1.3. Also, can you please explain what length Response $12 above means?

推荐答案

2种获取预测值的方法: 1.在过程物流中使用分数方法 2.将数据添加到原始数据集中，减去响应变量，然后在输出数据集中获得预测.

2 ways to get predicted values: 1. Using Score method in proc logistic 2. Adding the data to the original data set, minus the response variable and getting the prediction in the output dataset.

下面的代码都对这两种方法进行了说明:

Both are illustrated in the code below:

*Create an dataset with the values you want predictions for;
data pred_wanted;
input logvolume lograte;
cards;
1.5 1.3
;
run;

*append to predicted data set;
data vaso2;
set vaso pred_wanted;
run;

*run model with new options;
proc logistic data=vaso2 ;
  model Response(event='constrict')=LogRate LogVolume 
  /ctable pprob=0.5 selection=forward rsquare link=logit expb ;
  *Get output from vaso2 (method2);
  output out=estimates p=est_response;
  *Get output from pred_wanted(method1);
  score data=pred_wanted out=estimates2;
run;

这篇关于如何在SAS中进行逻辑回归预测概率?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！