Example for Cluster K-Means

A business analyst wants to classify 22 successful small-to-medium size manufacturing companies into meaningful groups for future analyses. The analyst collects data on the number of clients, rate of return, sales, and the years the companies have been in business. To start the partition process, the analyst divides the companies into three initial groups: established, mid-growth, and young.

  1. Open the sample data set, BusinessMetrics.MTW.
  2. Choose Stat > Multivariate > Cluster K-Means.
  3. In Variables, enter Clients 'Rate of Return' Sales Years.
  4. Under Specify partition by, select Initial partition column and enter Initial.
  5. Select Standardize variables.
  6. Click Storage. In Cluster membership column, type Final.
  7. Click OK in each dialog box.

Interpret the results

Based on the initial grouping provided by the business analyst, cluster k-means classifies the 22 companies into 3 clusters: 4 established companies, 8 mid-growth companies, and 10 young companies. Minitab stores the cluster membership for each observation in the Final column in the worksheet.

Cluster 1 (established companies) has the least variability of the 3 clusters, with the smallest value for the average distance from centroid (0.578). Cluster 1 also has the fewest observations (4).

Method

Number of clusters3
Standardized variablesYes

Final Partition

Number of
observations
Within
cluster
sum of
squares
Average
distance
from
centroid
Maximum
distance
from
centroid
         
Cluster141.5930.5780.884
Cluster288.7360.9641.656
Cluster31012.9211.0931.463

Cluster Centroids

VariableCluster1Cluster2Cluster3Grand
centroid
         
Clients1.23180.5225-0.91080.0000
Rate of Return1.29420.2217-0.69500.0000
Sales1.18660.5157-0.88720.0000
Years1.20300.5479-0.91950.0000

Distances Between Cluster Centroids

Cluster1Cluster2Cluster3
       
Cluster10.00001.59154.1658
Cluster21.59150.00002.6488
Cluster34.16582.64880.0000