Write Find's algorithm and explain with example

Write Find's algorithm and explain with an example

Answer:

Find's Algorithm: 

1. Initialize h to a most specific hypothesis. h = {'φ','φ','φ','φ','φ','φ'}.
2. For each positive example:

• for each attribute in the example:
• if (attribute value = hypothesis value)
• do nothing.
• else
• Replace the hypothesis value with more general constraint '?'.

flow chart of Algorithm:

Example:

Learning Concept: Days on which person enjoy the sport.

Data Set:

Sky	Temp	Humidity	wind	water	Forecast	sport
Sunny	warm	Normal	Strong	warm	same	Yes
Sunny	warm	High	Strong	warm	same	Yes
Rainy	cold	High	Strong	cool	change	No
Sunny	warm	High	Strong	warm	same	Yes

Step1:
Initialize h to the most specific hypothesis. h = {'φ','φ','φ','φ','φ','φ'} take the most specific hypothesis as your 1st positive instance.
h={'sunny', 'warm','Normal', 'Strong', 'warm', 'same'}

Step2:
Compare with another positive instance for each attribute, if (attribute value = hypothesis value) do nothing. else replace the hypothesis value with more general constraint '?'.

1. Since instance 2 is also positive so we will compare with it. In instance 2 attribute humidity is changing so we will generalize that attribute.

 h={'sunny', 'warm','?', 'Strong', 'warm', 'same'}

2. Instance 3 is negative so we will not consider it.

3. Instance 4 is positive and all attribute of instance 4 is similar to the hypothesis.

so based on find's algorithm the hypothesis for Days on which person enjoy the sport is.
 h={'sunny', 'warm','?', 'Strong', 'warm', 'same'}


Term Used:

General Hypothesis: If I tell my friend to bring some food he might bring pizza/burger/biryani/dosa any food because I didn't specify anything so he will do a general hypothesis.
Denoted by G ={'?', '?','?','?', '?','?'}

Specific Hypothesis: If I tell my friend to bring chicken double-layer king size burger from KFC then it is the specific hypothesis.

Denoted by h = {'φ','φ','φ','φ','φ','φ'}

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