January 2018
Intermediate to advanced
332 pages
7h 36m
English
Content preview from Hands-On Data Structures and Algorithms with JavaScript
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Calculating target entropy
Since we have two possible outputs for the Play Soccer (target) attribute, we will calculate the entropy using the frequency table (indicating how many times a particular value was received) of the target attribute:
The probability of receiving yes is the total times it was received divided by the total number of messages received and so on.
|
Play Soccer
|
|
|
Yes
|
No
|
|
9
|
4
|
So, the entropy of the target would be as follows:
targetEntropy = -( (9/13) log2 (9/13) ) - ( (4/13) log2 (4/13) );targetEntropy = 0.89049164021;
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