# In this example of fuzzy c-means, what is the difference between "sigma" and "center" for the clusters?

In this example, what exactly do "Cluster" and "Sigma" mean? (They chose random coordinates for the three centroids of the groups)

• Centers: Cluster centers, returned as a JxN array, where J is the number of clusters and N is the number of data dimensions.
• Sigma: Range of influence of cluster centers for each data dimension, returned as an N-element row vector. All cluster centers have the same set of sigma values.