Homework Problem Set 1, Due Friday September 4, 2009.
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(a) Give the R code lines to create an integer vector in 
your R workspace named W1 of length 240 with first 120 
elements consisting of  5,8,2,5,8,2,...  and last 120 
elements consisting of  1,4,2,0,1,4,2,0,...

(b) Give the R code lines to create a real numeric vector 
in your R workspace named  W2 of length 240 consisting of 
the values  cos(x/7)  for odd values  x , and  1/sqrt(1+0.3*x^2) 
for even values of  x , where the index  x = 1,2,... 240.

(c) Give the R code lines to create a boolean vector W3 of 
length 240 which has value "True" at every index x=1,..,240
where  W1 is 4 or 8, and has value "False" at every other index.

(d) Give the R code lines to create a character vector W4 of 
labels "A", "B", "C" where "A" appears at every index where 
the W3 value is "False", and "B" appears at every index where 
W3 is "True" and W2 is less than .17, and "C" appears at all 
other indices.

(e) Give the R code lines to create a matrix defined by 
binding together the vectors W1, W2, W3, W4 with column names 
"Seq", "Num", "TVal", and "Class" respectively. 
What is the "class" -- i.e., data-type -- of your matrix ?
What is the class of columns 2 and 3 of the matrix ?

(f) Give the R code lines to create a data-frame out of the 
same columns W1, W2, W3, W4 and with the same new column names 
as in (e). But in this part, make sure that columns 1 and 2 of 
the resulting data-frame remain numeric, column 3 remains 
boolean, while column 4 is of "character" type.

(g) Finally, define and print out in the form of a single 
labelled table or matrix lines 1,4,6,10,11,20,30,100,119 of 
the data-frame you created in (f).

YOU ARE RESPONSIBLE FOR CHECKING THAT THE R CODE YOU HAND IN
FOR PARTS (a)--(f) DOES EXACTLY WHAT IT IS SUPPOSED TO, BUT
DO NOT HAND IN THE PRINTED-OUT FORMS OF ALL OF THE VECTORS 
AND MATRIX AND COMPLETE DATA-FRAME YOU CREATE !

YOU MAY IF YOU LIKE HAND IN SOME INTERMEDIATE RESULTS, PERHAPS (A
SMALL) PART OF THE VECTORS, MATRICES, OR DATA-FRAMES YOU CREATE TO
DOCUMENT THAT YOU HAVE CODED YOUR COMMANDS CORRECTLY. BUT KEEP THIS
PART ALSO AS BRIEF AS POSSIBLE: EACH EXTRA ITEM YOU INCLUDE SHOULD
HAVE A SPECIFIC JUSTIFICATION AND INTERPRETATION AS A CHECK ON YOUR
WORK ! PLEASE INCLUDE SOME WORDS

### IN COMMENT LINES LIKE THIS

WITHIN THE CHECKING PORTIONS OF YOUR HANDED-IN PAPER TO EXPLAIN WHAT
YOU ARE DOING.