.L:55    
                ST 301
                Fall 1993   
                
                Assignment 5
                Due Fri. Oct. 8
                 
                  The file /ncsu/st301_info/horse.sas  contains measurements
                on blood flow, volume, and velocity in a horse.  These 
                measurements were made at the NCSU vet school every 15 seconds 
                for 3 hours after the horse received an injection.
                
                  Get into SAS, include this file 
                  (==> inc '/ncsu/st301_info/horse.sas)
                and execute the program. 

                1.   Explain what each command after the data is doing, for 
                example say PROC UNIVARIATE is computing the quartiles, 
                median, etc. then the OUTPUT statement is ......... 
                                         
                2.   Describe the output. What do the median blood flow and
                dispersion of blood flow look like as the 10 minute intervals 
                pass?   Do they change with time?  Are they more or less 
                constant?  Any trends?
                
                3.   Using a ruler and pencil and the output, create a 
                regression graph like that on page 106. 
                
                4.   Change the code and repeat steps 1-3 for the variables 
                volume and flow.
                
                5.   Using PROC PLOT; PLOT VOLUME*VELOCITY; create and hand in 
                a graph of VOLUME versus VELOCITY.  Describe any relationship 
                you see.  
                
                6.   Include the BOXREG macro as follws from the program 
                editor window: 
                         ==> inc '/ncsu/st301_info/boxreg.sas'
                and submit it so that it becomes known to SAS.
                
                Now submit this code:
                     PROC SORT DATA=HORSE; BY VELOCITY; 
                     DATA PART6; SET HORSE; T+1; 
                       GROUP = FLOOR((T-1)/40); 
                     PROC MEANS NOPRINT; VAR VELOCITY; BY GROUP; 
                       OUTPUT OUT=OUT1 MEAN=MNVEL; 
                     DATA BOTH; MERGE PART6 OUT1; BY GROUP; 
                     %BOXREG(BOTH,VOLUME,MNVEL); 
                     RUN;
                
                Describe what the graphs are telling you.  Note that this is 
                giving an exploratory regression like that on page 100.      
                     
                Begin reading Chapter 5.