STAT 540 Homework 6

1. Write a SAS program to read in the data file beatles_songlengths.txt 
given on the course web page. The variables are the name of the album and the lengths, 
given in minutes and seconds, of each of the 14 songs on the album.  (Note that two of 
these albums have only 13 songs.)  Name the variables album, min1, sec1, min2, sec2, and 
so on.

Use shortcut references for the variables to do the following:

Using arrays, create another set of variables songtime1,...,songtime14 giving the song 
lengths in minutes (including decimal places). (e.g.: 2 min, 30 sec = 2.5 minutes).
(HINT:  Use three different ARRAY statements, one for the minutes variables, one for 
the seconds variables, and one for the new songtime variables.  The syntax for each 
ARRAY statement should be basically the same --- only the array name and the variables' 
names will be different.)

Have SAS calculate (and store as a variable) the mean song length for each album.  

Finally, drop the original minutes and seconds variables and print the remaining data set using PROC PRINT.

2. Read in the data set nfl_season_data.txt which is on the course web page under the link 
"NFL players data (very long)" and under Data Files for Homework as "nfl_season_data.txt".  
Feel free to use the code in the "automatic variables" example to read in the data.  

Use PROC MEANS to calculate the 5-number summary (min, Q1, median, Q3, max) of the 
variable PassYD (ONLY for the players whose position is "qb");   
(Hint: use the WHERE statement to pick out the appropriate values of "position".)
This should be done SEPARATELY for each value of "team".

3. Look at the cake_data_duncan.txt (Duncan Hines brand) and cake_data_betty.txt (Betty 
Crocker brand) files on the course web page.  Read these in as separate data sets (the 
variables in each file are Flavor and Height).  Be sure when reading in each data set to create a variable 
for that data set that indicates the cake brand, which will have the same value  (either Duncan or Betty)
for each observation in the particular data set.  

(a) Stack these two data sets with a SET statement, and print the new (combined) data set.

(b) Merge the two data sets by flavor, and print the new (combined) data set. Be sure the 
merged data set indicates which cake brand goes with which height.

(c) Use PROC MEANS to calculate the mean and standard deviation of heights, for each 
flavor, writing the summary statistics to an output data set.  The PROC MEANS should 
be done on the stacked data set.

Merge these summary statistics with the stacked data set created in part (a) and print 
the resulting data set.  The resulting data set should be ordered or printed by flavor and 
should include at least columns for the brand, the height, the mean height (for each flavor), 
the standard deviation of height (for each flavor).


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NOTE:  You MUST intersperse comments in your SAS program to explain 
in detail what your SAS statements are supposed to be doing.  Please be generous with your 
comments, since you will be graded not only on the correctness of the code, but the 
clarity and amount of comments.  Remember that SAS comments are typed as:
/* comment */
or
*comment;

DO NOT put R-style comments (with #) in your SAS code!!!

You can upload your .txt file with your SAS code and comments into Blackboard as usual.

As with the other homeworks, to ensure that the grader will be able to grade your submission:

* Please save your document as a plain text (.txt) file before uploading.
* Please ensure that EVERY line in your submitted text file EXCEPT your SAS code is placed in "comments". 
That way, the grader will be able to copy everything in the file into SAS and have the program run without a problem.
* Please include detailed comments explaining your code.  You will be graded on the quality of your comments, as well as the correctness of your code.