DESCRIPTION

Please keep in mind the OMSI rules.

Save your files often.

Submit each answer individually and make sure you receive the
notification of successful submission.

Don't wait till the last moment to submit all answers, as there might be
network traffic in the last 5 minutes causing unexpected delay and
failure.  

Remember that clicking CopyQtoA will copy the entire question box to the
answer box.

In questions involving code which will PARTIALLY be given to you in the
question specs, you may need to add new lines.  There may not be
information given as to where the lines should be inserted. 

MAKE SURE TO RUN THE R CODE ANSWER IN PROBLEMS THAT INVOLVE R CODE!


QUESTION

(text answer - 20 pts) In our book, instead of set union we say
_______________________.


QUESTION -ext .R -run 'Rscript ./omsi_answer2.R'

(R code answer - 20 pts) We choose two letters from the word READING
without replacement. What is the probability that we draw an N and then
a G?

QUESTION

(text answer - 20 pts) Consider the Preferential Attachment Model, Sec.
2.13.1.  Let D_{i,j} denote the degree of node v_{i} immediately after
node v_{j} attaches to the network.  Define the events A = {D_{1,3} = 2}
and B = {N_3 = 2}.  Are A and B disjoint?  Are they independent?  Answer
D for disjoint only, I for independent only, B for both, and N for
neither.


QUESTION -ext .R -run 'Rscript ./omsi_answer4.R'

(R code answer - 20 pts)  Consider the bus problem, Sec. 2.11 (page 20).  
Find the probability that in the first 2 stops, a total of exactly 3 passengers board.


QUESTION -ext .R -run 'Rscript ./omsi_answer5.R'

(R code answer - 20 pts) In Sec. 2.14.6, we used runif() to simulate one
toss of a coin.  We could instead use sample() for this, filling in the
blanks below, in code that finds the approximate value of probability of
getting 2 heads in 2 tosses:

count <- 0
for (i in 1:nreps) {
   toss1 <- sample(          )
   toss2 <- sample(          )
   if (   ) count <- count + 1
}
print(count/nreps)