Thanks Reeza. Much clearer now. I think the author of the question didn't make state it clearly from the start. ... View more

From subsetting condition "... that is, if 'Sleep'<1 or 'Sleep'>12, then 'Sleep2'=. " seems sleep takes on positive values in the range 1 to 12 ? ... View more

Try this 🙂     /*Using for example instream dataset otherwise if you have SAS dataset, then SET statement*/ /* OPTION 1- Set outliers to missing in DATA step if you want the outliers to be replaced with missing values*/ /* OPTION 2- You need not set outliers to missing but subsetting WHERE statement in PROC MEANS works fine*/ DATA outliers; INFILE DATALINES; INPUT sleep age @@; IF (sleep LT 1 OR sleep GT 12) THEN sleep=.; DATALINES; 1 20 3 40 12 30 13 40 9 90 ; RUN; /*Print data to see if outliers are replaced with missing values*/ PROC PRINT DATA=outliers NOOBS; RUN; PROC MEANS DATA=outliers; VAR sleep age; WHERE sleep GE 1 AND sleep LE 12; RUN; ... View more

/*Create dataset*/ data create_data; infile datalines; input id t base value; datalines; 1 1 5.053078 14.61624 1 5 5.687529 36.09745 1 7 4.149219 45.9342 1 14 3.342423 72.15495 ; run; data want; set create_data end=last; by id t; /*Initialize variables*/ retain t_first 0 base1 0 t_first 0 t_last 0 value_last 0 t_diff 0 value_diff 0; /*Read base and t values for first observation*/ if first.id then do; base1=base; t_first=t; end; /*Read t and value values from last observation*/ if last.id then do; t_last=t; value_last=value; end; /*Perform calculation*/ t_diff=t_last - t_first; value_diff=value_last-base1; /*Subset the dataset for the last observation*/ if last then output; run; proc print data=want noobs; /*Displaying variables of interest*/ var t_first t_last t_diff base1 value_last value_diff; run; ... View more