Users unfamiliar with microarrays in general are encouraged to familiarize themselves with the the biology and technology behind the data. For this tutorial we assume the microarray data is gene expression measurements across several different conditions (eg. Different time points, different cell types, different treatments, etc.). The data will be needed to formatted into a gene expression data matrix, where each row is represents a gene and each column represents a different condition. A row in that matrix represents a gene expression vector, or the expression measurements for that gene across every assayed condition.