Log:

62   data stats;
63       set revenue;
64       array weekly{5} mon tue wed thu fri;
65   do i = 1 to 5;
66       total = weekly{i} * .25;
67       output;
68   end;
69   run;

NOTE: There were 2 observations read from the data set WORK.REVENUE.
NOTE: The data set WORK.STATS has 10 observations and 7 variables.
NOTE: DATA statement used (Total process time):
      real time           0.02 seconds
      cpu time            0.01 seconds

Commentary:
The statement array weekly{5} mon tue wed thu fri; defines an array for variables mon, tue, wed, thu, and fri are present in the dataset REVENUE. To process the array we need to use a loop. To define the loop the correct syntax is do i = 1 to 5; as this will process the array variables.

Below is the newly created WORK.STATS dataset:

Dataset(s):