Dendrogram:
Statistical distance is a measure calculated between two records that are typically part of a larger dataset, where rows are records and columns are variables. To calculate Euclidean distance, one possible distance metric, the steps are:
1. [Typically done, but not always] Convert all the values in each record to standardized values, on a variable by variable basis.
2. Subtract one record from the other, resulting in a vector of differences
3. Square the differences, sum them, and take the square root.