GROUP F CLUSTER ANALYSIS - session 4
-By
Amrita Bazray (14005)
In this class we
studied about cluster analysis, its purpose and how to use it in the business
context effectively through innovative thinking as mangers with a given set of
information.So what is it?Firstly a cluster is a
group of relatively homogeneous cases or observations.Cluster
analysis is a statistical method of partitioning a sample
into homogeneous classes to produce an operational classification which
identifies groups of samples that behave similarly or show similar
characteristics into meaningful taxonomies, groups, or clusters. It is a data
reduction tool that creates subgroups that are more manageable than individual
datum.
It makes no distinction
between dependent and independent variables.·
Hierarchal- for more than 50 objects
·
Divisive clustering/ top-down
clustering
·
Agglomerative clustering- successively
merge (or agglomerate) pairs of clusters until all clusters have been merged
into a single cluster that contains all documents. Also called HAC.
·
K-means-
for less than 50 objects
Procedure:
1. Selection of variables-
Based on the objective of clustering.
2. Distance measurement-
Difference between the two individual objects. Data can be Interval, binary and
counts. (Euclidean distance, Block etc.). For counts we use Chi square. For
Binary we use squared Euclidean distance method. For business purposes usually
we have data in the form of either interval or binary.
3. Clustering criteria-
Methods used are nearest and furthest neighbor method and centroid clustering
(mostly used)
If
we discuss the first method of cluster analysis i.e. Hierarchical
cluster analysis, we follow the above given procedure. We
were taught that to carry out a hierarchical cluster analysis we usually use
Ward’s method applying Euclidean Distance as the distance or similarity
measure.
The
results of the cluster analysis are shown by a dendrogram, which lists all of the samples and it indicates at
what level of similarity any two clusters were joined.
Medici effect-
author Frans Johansson. It relates to the concept of innovation and
perspective. In this book he shares many interesting stories of
cross-pollination between disciplines that result in explosion of new ideas and
innovation. It is recommended that all students should read this book.
No comments:
Post a Comment