ST 610N -- Fall 2006  
       HOMEWORK 3 ** Revised **
       DUE THURSDAY, 05 October 2006

       EXERCISES

       1) Write SAS code to read two variables, MONTH and YEAR
       and determine the numbers of days (DAYS) in that month 
       in that year.  Be careful of leap years and century 
       anomalies in the Gregorian calendar.  Recall that if
       the year is divisible by 100, it is NOT a leap year
       unless it is divisible by 400, so that the year
       1900 was NOT a leap year, but 2000 was a leap year.

       Demonstrate your code with some examples -- use at least 10.
       
       Hint: See demo of logical operator 'in' which looks like
         x in( ..list of elements.. )
       in the file oct02.ex1 in the oct06 directory. 

       2) In the file hwkgrade.dat are the homework scores for
       a course I taught a few years ago.  The first three characters
       are the initials of the student.  The remainder of each record
       are the scores for 12 homeworks.  One record is for a special
       student (Maxi Mum) who got a perfect score on each homework --
       this student is 'MUM.'  Create a SAS dataset (and print it) 
       with the following information:

       initials of student 
       number of missing homeworks
       sum of homework grades
       sum of homework grades with the lowest (or missing) dropped

       Sort the dataset so that the top student (Maxi Mum) is at
       the top.