Here below is a data table:

To count the following information for each class: total number of students, the average score of individual total score, the code is as follows:

=spl("=E(?1).groups(Class;count(1):TotalNumber,avg(Math+English+PE):AverageScore)",A1:E11)

esProc Desktop and Excel Processing
6.13 Find out interval in which a certain condition occurs continuously
7.2 Conditional aggregation