The OUTPUT statement creates the SUMSTAT data set and
outputs the mean value for the final grade to the new variable AverageGrade.
IDGROUP outputs the name of the student with the top exam score to the variable
BestScore and the observation number that contained the top score. WAYS and
LEVELS output information on how the class variables are combined.
output out=sumstat mean=AverageGrade
idgroup (max(score) obs out (name)=BestScore)