.L:55    
                               
                                             
                ST 301
                Fall 1993   
                
                Instructor:
                D. A. Dickey 
                
                Assignment 4
                Due Wed. Sept. 29
                 
                Using SAS, create the schematic diagrams (side-by-side box 
                plots) asked for in exercises 2 and 4 (pp 75 and 76).  In 
                addition, for exercise 2, create (by hand is easiest) a 
                side-by-side stem and leaf display as shown in your class 
                handout. OPTIONAL: To clean up your output,  you could go to 
                the command line in the output window and type  
                ==> file 'junk'.  Then go to the program editor window and type 
                ==> inc 'junk' and then delete the unwanted portions of the 
                output.  
                
                Here are some letter grades for three sections of a course. The 
                teacher name, class size, and list of grades is given below.

                teacher   n      grades
                Smith   37 A B A A C A D C C D C B F B B D C D C C C A C A A B
                           D C B F C B D F C A A     
                Willis  24 B A B C C D C C D D B A B D C C D C B B A F B F
                Johnson 55 A C C B A A B B B C A C D C C F C D C B B A A A B B
                           A B F C C B B A B B A B B A C D B A A B C D C B A A
                           B A A 

                Make a two way frequency table with rows representing grades
                and columns representing teachers. Use PROC FREQ in SAS or do 
                it by hand.  As on page 77, report marginal frequencies.  

                Make a relative frequency table for the grades data like the 
                table on page 78.  You'll have the relative frequencies for
                each teacher and pooled across teachers. You can use PROC FREQ 
                or do this by hand.  
     
                Using SAS, produce and hand in a bar chart of grades for each 
                teacher.  
                hint: Include '/ncsu/st301_info/hwk6.sas' to get the 
                data.  Now run PROC CHART; HBAR GRADES/TYPE=PERCENT 
                GROUP=TEACHER G100; 
                                                  
                From this, by hand if you like, make a comparison bar chart of 
                grades by teacher where the first group of bars represents the 
                A's, the second the B's, etc. Within each grade grouping, of 
                course, you'll have a bar for each teacher.  You can leave out 
                the bar for the average if you like.  
                
                Reading 
                Finish reading Chapter 3.  Be sure you understand exactly
                how comparison bar charts are to be constructed and how
                to interpret them.
                               

                REMINDER - Test 1 on Chapters 1 and 2 and our intro to SAS will 
                be held on Sept. 27.