Cluster analysis is a statistical technique used to group similar objects into clusters. It can be used to reduce the complexity of large datasets by organizing data into a smaller number of homogeneous groups. The key advantages are that it provides a way to classify unclassified data with accuracy while saving resources like time and money. There are different types of cluster analysis methods like hierarchical, centroid-based, distribution-based, and density-based clustering that organize objects into clusters in different ways. Cluster analysis has various applications in fields such as marketing, land use planning, insurance, and earthquake studies.