is variable selection the same as clustering what's the difference between a cluster and a variable selection? why is variable selection important what is the difference between a cluster and variable selection how does variable selection work in clustering difference between clustering and variable selection how do we cluster variables what is the difference between clustering and variable selection which data is considered variable selection in clustering what is clustering in math what is the difference between a cluster and a variable selection problem why is variable selection important for clustering what is the difference between cluster and variable selection what is clustering and variable selection is clustering and variable selection the same thing? what is the difference between clustering and variable selection in unsupervised learning? how to do clustering can variable selection and clustering be used together what is a cluster and variable selection why is variable selection and clustering important