Difference between classification and clustering in data mining? [closed]

Answer 1

Classification: Predict results in a discrete output => map input variables into discrete categories

Popular use cases:

1. Email classification : Spam or non-Spam

2. Sanction loan to customer : Yes if he is capable of paying EMI for the sanctioned loan amount. No if he can't

3. Cancer tumour cells identification : Is it critical or non-critical?

4. Sentiment analysis of tweets : Is the tweet positive or negative or neutral

5. Classification of news : Classify the news into one of predefined classes - Politics, Sports, Health etc

Clustering: is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense) to each other than to those in other groups (clusters)

Popular use cases:

1. Marketing : Discover customer segments for marketing purposes

2. Biology : Classification among different species of plants and animals

3. Libraries : Clustering different books on the basis of topics and information

4. Insurance : Acknowledge the customers, their policies and identifying the frauds

5. City Planning : Make groups of houses and to study their values based on their geographical locations and other factors.

6. Earthquake studies : Identify dangerous zones

7. Recommendation system :

References:

geeksforgeeks

dataaspirant

3leafnodes

Answer 2

Classification- A data-set can have different groups/ classes. red, green and black. Classification will try to find rules that divides them in different classes.

Custering- if a data-set is not having any class and you want to put them in some class/grouping, you do clustering. The purple circles above.

If classification rules are not good, you will have mis-classification in testing or ur rules are not correct enough.
if clustering is not good, you will have lot of outliers ie. data points not able to fall in any cluster.

Answer 3

I'm a new comer to Data Mining, but as my textbook says, CLASSICIATION is supposed to be supervised learning, and CLUSTERING unsupervised learning. The difference between supervised learning and unsupervised learning can be found here.