## What is clustering in K-means algorithm?

K-Means Clustering is an Unsupervised Learning algorithm, which groups the unlabeled dataset into different clusters. Here K defines the number of pre-defined clusters that need to be created in the process, as if K=2, there will be two clusters, and for K=3, there will be three clusters, and so on.

**How K-means algorithm works explain?**

It calculates the sum of the square of the points and calculates the average distance. When the value of k is 1, the within-cluster sum of the square will be high. As the value of k increases, the within-cluster sum of square value will decrease.

### What are clustering methods?

Clustering methods are used to identify groups of similar objects in a multivariate data sets collected from fields such as marketing, bio-medical and geo-spatial. They are different types of clustering methods, including: Partitioning methods. Hierarchical clustering. Fuzzy clustering.

**How does k-means clustering select its clusters?**

In k-means clustering, the number of clusters that you want to divide your data points into i.e., the value of K has to be pre-determined whereas in Hierarchical clustering data is automatically formed into a tree shape form (dendrogram).

## When to use K-means vs hierarchical clustering?

A hierarchical clustering is a set of nested clusters that are arranged as a tree. K Means clustering is found to work well when the structure of the clusters is hyper spherical (like circle in 2D, sphere in 3D). Hierarchical clustering don’t work as well as, k means when the shape of the clusters is hyper spherical.

**How many types of clustering techniques?**

Clustering itself can be categorized into two types viz. Hard Clustering and Soft Clustering. In hard clustering, one data point can belong to one cluster only.

### How many clusters in K-means?

The optimal number of clusters can be defined as follow: Compute clustering algorithm (e.g., k-means clustering) for different values of k. For instance, by varying k from 1 to 10 clusters. For each k, calculate the total within-cluster sum of square (wss).

**How many clusters in k-means clustering?**

The optimal number of clusters k is the one that maximize the average silhouette over a range of possible values for k. This also suggests an optimal of 2 clusters.

## Is k-means supervised or unsupervised?

unsupervised learning algorithm

K-Means clustering is an unsupervised learning algorithm. There is no labeled data for this clustering, unlike in supervised learning. K-Means performs the division of objects into clusters that share similarities and are dissimilar to the objects belonging to another cluster.

**What are the main differences between k-means and the Dbscan clustering techniques list two differences?**

DBSCAN

K-Means | DBSCAN |
---|---|

K-means needs a prototype-based concept of a cluster. | DBSCAN needs a density-based concept. |

K-means has difficulty with non-globular clusters and clusters of multiple sizes. | DBSCAN is used to handle clusters of multiple sizes and structures and is not powerfully influenced by noise or outliers. |

### How do K-means clustering methods differ from K nearest neighbor methods?

The ‘K’ in K-Means Clustering has nothing to do with the ‘K’ in KNN algorithm. k-Means Clustering is an unsupervised learning algorithm that is used for clustering whereas KNN is a supervised learning algorithm used for classification.

**How do you choose K for k-means clustering?**

Calculate the Within-Cluster-Sum of Squared Errors (WSS) for different values of k, and choose the k for which WSS becomes first starts to diminish. In the plot of WSS-versus-k, this is visible as an elbow. Within-Cluster-Sum of Squared Errors sounds a bit complex.

## When to use k means clustering?

K-Means Clustering: K-means clustering is a type of unsupervised learning method, which is used when we donâ€™t have labeled data as in our case, we have unlabeled data (means, without defined categories or groups). The goal of this algorithm is to find groups in the data, whereas the no. of groups is represented by the variable K.

**When to use k means?**

kmeans performs k -means clustering to partition data into k clusters. When you have a new data set to cluster, you can create new clusters that include the existing data and the new data by using kmeans.

### What is k – means cluster?

K-means clustering is a method used for clustering analysis, especially in data mining and statistics. It aims to partition a set of observations into a number of clusters (k), resulting in the partitioning of the data into Voronoi cells. It can be considered a method of finding out which group a certain object really belongs to.

**What is clustering and different types of clustering methods?**

Centroid-based Clustering. Centroid-based clustering organizes the data into non-hierarchical clusters,in contrast to hierarchical clustering defined below.