[SOLVED] Average/deviation by group

I have a data set  where one of the columns is category. And I want to calculate the mean and standard deviation of some other column, but separately for each category.

Ie., for input like

GroupName...Value
A.......................1
A.......................3
B......................1
B.......................5

I want the output like

GroupName...Value...Mean...StdDev
A.......................1...........2...........1.44          
A.......................3...........2...........1.44
B.......................1...........3...........2.8
B.......................5...........3...........2.8


I know how to get the group means and standard deviations via Aggregate operator, but I dont know how to add the new columns to the original dataset. What am I missing?

Thanks!