CSCI 4380 Data Mining, Midterm Exam 12 Q&A
In a single-server queue simulation, if the arrival rate of
customers showing up is greater than the service rate of the single-server, then a
long queue will only rarely be
...
CSCI 4380 Data Mining, Midterm Exam 12 Q&A
In a single-server queue simulation, if the arrival rate of
customers showing up is greater than the service rate of the single-server, then a
long queue will only rarely be formed.
Question 2 3/3pts
Consider a family that has 2 children. Assume that
Pr(kid is a boy) = 1/3 and Pr(kid is a girl) = 2/3 and that
the genders of the 2 kids are independent. What is the probability
that both kids are girls given that we know at least 1 of them is a girl?
1/8
E
Question 3 3/3pts
or ? Simulations can be used to study detailed relations that might
be lost in other types of analyses, for instance, exact equations.
Question 4 3/3pts
The planet Tranya has 120-day years. Suppose there are three Tranyanians in the
room. What is the probability that at least two of them share the same birthday?
0.015
0.025
0.035
0.149
Question 5 0/3pts
or ? The function f(z) = 5e~*/® for z > 0 s a valid
p.d.f.
oo S
|
Question 6 3/3pts
Suppose that X is a continuous random variable with p.d.f. f(z)
01|X>1/2).
= o
Question 7 3/3pts
If X ~ Bern(0.5). find E[e*¥].
1.38
Question 8 3/3pts
Suppose X and Y are continuous random variables with joint p.d.f.
f(z,y) = czy?,0 < z < 2,0 < y < 1, for some appropriate constant c. Find
E[2X +1].
EE oo
Suppose X and Y are discrete random variables with the following joint p.m.f.
fl@y) [ X=2 X=3 | Pr(Y=y)
0.2 0.5 0.7
Y=1 0.0 0.3 0.3
Pr(X=gz)| 0.2 08 | 10
Find Var(X + 2Y).
= oo
Question 10 3/3pts
Suppose that X and ¥ have joint p.df. f(z,y) = cze?/(1+ 1) for
0
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Question 23 SIS
In the course of a simulation study at Disneyworld, we provide our
client with confidence intervals for the mean customer waiting time
in front of the Space Mountain attraction. What step of the
simulation study process is this?
) “ Output Analysis
Question 24 3/3pts
or ? A conditional wait is a wait time of unspecified length, e.g..a
customer waiting time.
D .
Question 25 SIS
or ? Entities can be permanent (iie a machine) or temporary (iike a
customer).
EE .
Question 26 3/3pts
1f and y are two consecutive event times in a discrete-event simulation model,
what can happen in the time intervalz < ¢ < y?
The system state cannot change
Question 27 3/3pts
or ? The simulation clock is a variable that represents simulated
time.
Question 28 it
Which of the following is about the Fixed-Increment time-advance
mechanism?
This approach allows the simulation clock o move both backward and forward in
fxed time increments.
Question 29 it
or ? Deep down inside almost al discrete-event simulation
software packages, you willfind an event-scheduling routine.
Question 30 3/3pts
or ? Most of the programming effort involved in the EventScheduling modeling approach comes from keeping track of the event
bookkeeping.
Question 31 s
In Arena, what modules would | need to generate customer arrivals, and then
have each arrival go to server Awith probability 0.5 (else to server B with
probability 0.5)2
GENERA
ARRIVE
CREATE, DECIDE, and two PROCESS modules
CREATE, PROCESS, DISPOSE
Question 32 3/3pts
or ? In Arena, it s not possible to use a single DECIDE module to
randomly route customers to one of three or more destinations.
Question 33 3/3pts
Which of the following modules can not be found in the Arena Basic Process
template?
DECTDE
CREATE
TRANSPORT
Question 34 1/1pts
Jackets or tus? (No excuse to make a mistake here!)
Jackets
Question 11 3/3pts
or ? If the covariance of X and Y’ is non-zero, then it s still possible
for X and Y to be independent.
Question 12 3/3pts
Suppose that X and Y are identically distributed with a mean of 3and a
variance of 20, and Cov(X, Y) = 10. Find Var(X + 2Y).
140
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