# Outliers Approach

Having a schema which the majority of the values are IDs. Like this example (this isn't my real data):

ID   SCHOOL_ID   CLASSE_ID   STUDENT_ID   GRADE
1       1            1           1          17
2       1            1           2          10
3       1            1           3          4
4       1            2           19          11
5       1            2           21         8
...    ...          ...         ...         ...


Which one of this can be a better approach to detect outliers using SQL: - Standard Deviation + Average - Try to implement an clustering algorithm