CODEWITHSUNDEEP
decision-tree
Chao Li
Chao Li

Reputation: 169

how to calculate accuracy from decision trees?

enter image description here

Hi, I am taking a course on Coursera and came into this question. My answer is 1-(4048+3456)/8124=0.076. However, the answer is 0.067. Anybody can help me to solve this? Thank you!!

Upvotes: 16

Views: 47615

Answers (3)

Pankaj Singh
Pankaj Singh

Reputation: 1

Though answer is correct but the confusion matrix looks not correct. This should be the confusion matrix( for depth-2). enter image description here

Upvotes: 0

Ashish Anand
Ashish Anand

Reputation: 2743

First We will draw confusion metrics for both cases and then find accuracy.

Confusion metrics:

enter image description here

Accuracy= (TP + TN) / (Total number of observation)

Accuracy calculation:

Depth 1: (3796 + 3408) / 8124

Depth 2: (3760 + 512 + 3408 + 72) / 8124

Depth_2 - Depth_1 = 0.06745

Upvotes: 13

patricio
patricio

Reputation: 314

Accuracy: The number of correct predictions made divided by the total number of predictions made.

We're going to predict the majority class associated with a particular node as True. i.e. use the larger value attribute from each node.

So the accuracy for:

  • Depth 1: (3796 + 3408) / 8124
  • Depth 2: (3760 + 512 + 3408 + 72) / 8124

Depth_2 - Depth_1 = 0.06745

Upvotes: 22

Related Questions