CS108L Spring 2013
Week 7: Quiz
1. What is a computer simulation?
a) A device that can be used to simulate a computer.
b) A computer code that explores how a computer can be used in the real
world.
c) ****Running the computer model to simulate the passage of time and
exploring the behavior of the modeled system.
d) An abstraction of the real world that captures the elements of the
system and the behavior of the elements being modeled.
e) Something that you teacher tells you to do on the computer.
2. What is a deterministic computer simulation?
a) A simulation that gives you numbers for an answer.
b) A simulation that actually can be used to determine something.
c) A simulation that is being run by people who are determined to get the
correct answer.
d) ***A simulation that does not involve randomness and provides single
outputs for each set of inputs.
e) A simulation that was written by a very determined programmer.
3. What is a stochastic computer simulation?
a) ***A simulation that can produce different outputs for the same set of
inputs because randomness is involved.
b) A simulation that can be used to develop an understanding of problem
based on the chaste system in India.
c) A simulation that uses the stochastic algorithm developed by a
programmer named Stochast.
d) A simulation with inputs that are set using a uniform random
distribution.
e) A simulation with inputs that are set using a normal random
distribution.
4. When performing a simulation using a stochastic model and analyzing the
results of the simulation which of the following should you NOT do?
a) Sweep or vary the input parameters.
b) Repeat simulation runs at each set of input parameters since
stochastic models involve randomness and that may vary the
outcome..
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c) Record the input parameters that were used to generate each output
obtained.
d) ***Randomly select input parameters until you get the results you are
looking for.
e) Test the model by running it with input parameters for which the
correct output is known.
5. Why do you need to repeat runs of a stochastic simulation at the same input
parameters?
a) Because you teacher wants to torture you, repeatedly.
b) Because that is what the computer lab tells you to do.
c) Because you are not sure you entered the input parameters correctly.
d) Because a model that is stochastic, from Greek stokhastikos which
means “capable of guessing”, must be validated by showing that the
same input parameters always produce the same output.
e) ***Because you must average the results for each set of input
parameters to get a representative answer.
6. Which of these things is negative feedback for a population of rabbits?
a) Plants that rabbits can eat which grows more quickly in the presence
of rabbit poop.
b) ***A debilitating disease that the rabbits catch when they encounter
another rabbit.
c) A non-native, rodent species that eats a different kind of plant than the
rabbits eat.
d) Punishing the rabbits with a small electric shock when they try to exit
their safe and protected habitat.
e) All of the above.
7. You define a breed in NetLogo by:
a) Defining it anywhere in your program using the “set” command, as
long as it is defined before you use the breed.
b) Defining it anywhere in your program using the “let” command, as
long as it is defined before you use the breed.
c) Defining it by setting its shape in the setup procedure.
d) ***Defining it at the top of your program using the “breed” command.
e) Defining it anywhere in your program using the “breed” command, as
long as it is defined before you use the breed.
8. What are the three ways to create turtles in NetLogo?
a) Create, Spawn, Breed
b) ***Create, Sprout and Hatch
c) Spawn, Sprout, Breed
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d)
e)
Hatch, Spawn, Make
Procreate, Sprout, Breed
9. Will the following NetLogo code hatch any turtles?
turtles-own [energy]
to go-one-time
set energy 0
ask turtles
[
forward 1
set energy (energy – 1)
if (energy < 0) [ die ]
if (pcolor = green) [ set energy (random 25) ]
if energy > 10 [hatch 1]
]
end
a)
b)
c)
d)
Yes all the turtles will give birth to turtles.
Yes, on average, a bit more than half of the turtles will give birth.
Yes, on average, a bit less than half of the turtles will give birth.
Maybe yes, maybe no. It depends on the value of (random 25) for each
turtle.
e) ***No, the turtles will all die because their energy level drops to less than 0
when the turtle moves
10. The reading of Blown-to-Bits says we leave digital fingerprints when we use
our computers and access the Internet because_____
a) ***Accessing the Internet means downloading information to the
computer, some part of the system must know where we are to do that.
This leaves a trail.
b) People often choose to fill out forms on the Internet and enter personal
information.
c) People often choose to use school or company owned computers to
access the Internet and these computers are often monitored.
d) People sometimes use computers with viruses or other malware which
can track all the user’s accesses.
e) Even in a dry climate like New Mexico, people always have some oils
on their fingers – this is especially true when eating at the keyboard.
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