After we got a lot of samples and analyzed the concentrations of many compounds in them, we may ask about the relationship between the samples. You might have the sampling information such as the date and the position and you could use boxplot or violin plot to explore the relationships among those categorical variables. However, you could also use the data to find some potential relationship.
But how? if two samples’ data were almost the same, we might think those samples were from the same potential group. On the other hand, how do we define the “same” in the …