Pollution and temperature have higher contributions than before but depth still plays the
largest role in this particular example, even after standardization. But this contribution is
justified now, since it does show the biggest standardized difference between the samples.
We call this the standardized Euclidean distance, meaning that it is the Euclidean distance
calculated on standardized data. It will be assumed that standardization refers to the form
defined by (4.5), unless specified otherwise.
We can repeat this calculation for all pairs of samples. Since the distance between sample
A and sample B will be the same as between sample B and sample A, we can report these
distances in a triangular matrix – Exhibit 4.5 shows part of this distance matrix, which
contains a total of ½´30´29 = 435 distances.