Question

我正在尝试从心脏病学-weka.arff了解WEKA J48决策树。

我已按以下方式运行输出，

Test mode:10-fold cross-validation

=== Classifier model (full training set) ===

J48 pruned tree
------------------

thal = Rev
|   chest-pain-type = Asymptomatic: Sick (79.0/7.0)
|   chest-pain-type = AbnormalAngina
|   |   #colored-vessels = 0
|   |   |   peak <= 0.1: Healthy (4.0)
|   |   |   peak > 0.1: Sick (3.0/1.0)
|   |   #colored-vessels = 1: Sick (2.0)
|   |   #colored-vessels = 2: Healthy (0.0)
|   |   #colored-vessels = 3: Healthy (0.0)
|   chest-pain-type = Angina
|   |   cholesterol <= 229: Healthy (3.0)
|   |   cholesterol > 229
|   |   |   age <= 48: Sick (2.0)
|   |   |   age > 48: Healthy (3.0/1.0)
|   chest-pain-type = NoTang
|   |   slope = Flat
|   |   |   #colored-vessels = 0
|   |   |   |   blood-pressure <= 122: Healthy (3.0)
|   |   |   |   blood-pressure > 122: Sick (3.0)
|   |   |   #colored-vessels = 1: Sick (5.0)
|   |   |   #colored-vessels = 2: Sick (0.0)
|   |   |   #colored-vessels = 3: Sick (3.0/1.0)
|   |   slope = Up: Healthy (7.0/1.0)
|   |   slope = Down: Healthy (1.0)
thal = Normal
|   #colored-vessels = 0: Healthy (118.0/12.0)
|   #colored-vessels = 1
|   |   sex = Male
|   |   |   chest-pain-type = Asymptomatic: Sick (9.0)
|   |   |   chest-pain-type = AbnormalAngina: Sick (2.0/1.0)
|   |   |   chest-pain-type = Angina: Healthy (3.0/1.0)
|   |   |   chest-pain-type = NoTang: Healthy (2.0)
|   |   sex = Female: Healthy (13.0/1.0)
|   #colored-vessels = 2
|   |   angina = TRUE: Sick (3.0)
|   |   angina = FALSE
|   |   |   age <= 62
|   |   |   |   age <= 53: Healthy (2.0)
|   |   |   |   age > 53: Sick (4.0)
|   |   |   age > 62: Healthy (5.0)
|   #colored-vessels = 3: Sick (6.0/1.0)
thal = Fix
|   #colored-vessels = 0
|   |   angina = TRUE: Sick (3.0/1.0)
|   |   angina = FALSE: Healthy (5.0)
|   #colored-vessels = 1: Sick (4.0)
|   #colored-vessels = 2: Sick (4.0)
|   #colored-vessels = 3: Sick (2.0)

Number of Leaves  :     32

Size of the tree :  49


Time taken to build model: 0.03 seconds

=== Stratified cross-validation ===
=== Summary ===

Correctly Classified Instances         222               73.2673 %
Incorrectly Classified Instances        81               26.7327 %
Kappa statistic                          0.4601
Mean absolute error                      0.3067
Root mean squared error                  0.4661
Relative absolute error                 61.8185 %
Root relative squared error             93.5807 %
Total Number of Instances              303     

=== Detailed Accuracy By Class ===

               TP Rate   FP Rate   Precision   Recall  F-Measure   ROC Area  Class
                 0.696     0.236      0.711     0.696     0.703      0.756    Sick
                 0.764     0.304      0.75      0.764     0.757      0.756    Healthy
Weighted Avg.    0.733     0.273      0.732     0.733     0.732      0.756

=== Confusion Matrix ===

   a   b   <-- classified as
  96  42 |   a = Sick
  39 126 |   b = Healthy

问题是

j48选择哪个属性作为顶级决策树节点？
绘制一个图表，显示前两个的属性和值 J48的级别创建了决策树。

到目前为止，我只能解释关于正确分类的混淆矩阵。任何帮助将不胜感激。

Answer 1

最顶层的节点是＆＃34; thal＆＃34;，它有三个不同的级别。

您可以使用＆＃34; visualize tree＆＃34;在weka中将树绘制为图表。。在模型结果上，左键单击或右键单击＆＃34; J48 - 20151206 10:33＆＃34; （或类似的东西）。亲自尝试或搜索我提供截图的答案（如何执行此操作）

你可以通过＆＃34;修剪＆＃34;来约束树。它在J48配置对话框中为n级。

J48使用WEKA输出决策树节点

1 个答案: