SAS calculations in datastep

Question

I read a lot about the first. and last. function and basic calculations in SAS, though I want to circumvent the following problem in the datastep (if possible):

I need to flag each observation that exceeds the 25th percentile in each direction. Ie I want to calculate outliers and give them either a 1 or 0 (outlier or not). The problem I have is that I want to do it for a group/class of observations in the dataset.

Group Value OutlierFlag
a    1     1
a    10    0
a    11    0
a    400   1
b    2     0
b    2     0
b    500   1

To complicate/advance: I need to add a time-grid which means I need to sum all observations each minute and write down the value onto a kind of grid (the current observations are not in specified time intervals). I already produced the grid (minute steps). But how can I sum up observations and include them into the grid datastep in each minute observations? I am sorry if this is too blurry but maybe one of you knows how to do that or has an idea. I am very thankful!

Best!

EDIT:

Alright, I tested:

proc means data = MM.Data median P25 P75; 
class Security;
ods output Summary=mm.Data_median; 
var price spread; run; 

data mm.data; set mm.Data_median;
run; 

That basically gives me the Proc Means Output. But I want the original dataet filled with the p25 and p75 variables. Then I tried:

proc sql; 
create table mm.newData as select *, sum(spread) as sumspread 
from mm.Data 
group by RIC; quit; 

But it firstly groups it again and then there is no P25 function (I just entered sum for trial reasons).

Answer 1

• Add STACKODS & NWAY options to Proc means. This only calculates at highest level (ie only at group levels) and keeps data wide.

• Merge in using BY Group

   proc means data=sashelp.class nway stackods median p25 p75; class sex; var weight; ods output summary=stats; run; proc sort data=sashelp.class out=class; by sex; data want; merge class stats (keep=sex median p25 p75); by sex; flag_p75=ifn(weight>p75, 1, 0); run;