Question

Suppose I’ve a dataset in the form:

A B C
1 3 5
1 4 8
1 3 3
2 2 2
2 7 6
2 3 3
3 4 4 
3 4 7
3 2 8

Now, I want to take weighted average of each segment of A and then add them up over A. For example in A var for 1, I want to take the weighted avg as (3*5+4*8+3*3)/(3+4+3). And then add up to get 5.6. Same with other 2 segments of A. So, finally the table looks like the following:

A B C   D
1 3 7 5.6
2 6 6 7
3 5 9 8.2

Thank you.

Answer 1

You can find the solution below. I am curious about your result. For A=2, the weighted average should be (2*2+7*6+3*3)/(2+7+3), about 4.5. Why here you have 7?

data test;
input a  b  c ;
datalines;
1 3 5
1 4 8
1 3 3
2 2 2
2 7 6
2 3 3
3 4 4 
3 4 7
3 2 8
;
run;

proc sql;
create table agg as 
select a, b, c, sum(b*c)/sum(b) as d from test
group by a;
quit;

proc sort data=agg nodupkey;
by a d;
run;