Comp Sci unit 3 #10

A researcher wrote a program to simulate the number of mice in an environment that contains predators. The program uses the following procedures.

Based on the code, which of the following assumptions is made in the simulation?

• The number of mice increases by 1 each day.

• The number of mice does not change from day to day.

• The number of predators increases by 1 each day.

• The number of predators does not change from day to day.

Which of the following is a benefit of using a simulation instead of an experiment to make a prediction?

Select two answers.

response - correct

Responses

• A simulation allows investigation of a phenomenon without the real-world limitations on time, safety, or budget.

• 
  A simulation can be used to model real-world events that are impractical for experiments.

• A simulation always produces the same output, so its results can be verified.

• A simulation produces results that are more accurate than experimental results.

Flight simulation software, which imitates the experience of flying, is often used to train airline pilots. Which of the following is LEAST likely to be an advantage of using flight simulation software for this purpose?

• Flight simulation software allows pilots to practice landing in a variety of different terrains and weather conditions without having to physically travel.

  
  

• Flight simulation software could save money due to the cost of maintenance and fuel for actual training flights.

• Flight simulation software provides a more realistic experience for pilots than actual training flights.

• Flight simulation software allows for the testing of emergency air situations without serious consequences.

A city planner is using simulation software to study crowd flow out of a large arena after an event has ended. The arena is located in an urban city. Which of the following best describes a limitation of using a simulation for this purpose?

Responses

• The model used by the simulation software cannot be modified once the simulation has been used.

• The model used by the simulation software often omits details so that it is easier to implement.

• Running a simulation requires more time to generate data from trials than observing the crowd exiting the arena at various events.

• Running a simulation requires a large number of observations to be collected before it can be used to explore a problem.

Consider the following code segment, which is intended to store ten consecutive even integers, beginning with 2, in the list evenList. Assume that evenList is initially empty.

i ← 1

REPEAT 10 TIMES

{

<MISSING CODE>

}

Which of the following can be used to replace <MISSING CODE> so that the code segment works as intended?

• APPEND(evenList, i)

  i ← i + 2

• i ← i + 2

  APPEND(evenList, i)

• APPEND(evenList, 2 * i)

  i ← i + 1

• i ← i + 1

  APPEND(evenList, 2 * i)

Shoppers at a mall were asked whether they preferred wearing gloves or mittens in cold weather. Shoppers’ preferences were stored in the list voteList as strings, with the string "Gloves" representing a preference for gloves and the string "Mittens" representing a preference for mittens.

The following code segment is intended to traverse the list and display the number of shoppers who chose gloves and the number of shoppers who chose mittens.

numGlovesVotes ← 0

numMittensVotes ← 0

<MISSING CODE>

{

IF(vote = "Gloves")

{

numGlovesVotes ← numGlovesVotes + 1

}

ELSE

{

numMittensVotes ← numMittensVotes + 1

}

}

DISPLAY(numGlovesVotes)

DISPLAY(" shoppers chose gloves and")

DISPLAY(numMittensVotes)

DISPLAY(" shoppers chose mittens.")

Which of the following should replace <MISSING CODE> so that the code segment works as intended?

Responses

• IF(vote ≤ LENGTH(voteList))

• FOR EACH vote IN voteList

• REPEAT LENGTH(voteList) TIMES

• REPEAT UNTIL(vote > LENGTH(voteList))

A group of planners are using a simulation to examine whether or not a park that they are designing is going to affect foot traffic in the area. The simulation uses a model that includes input variables for the park such as the number of entrances, sidewalks, and bike trails and the square footage of open space (grassy areas). The simulation can then be run multiple times using different values for the input variables to represent different park designs.

However, the simulation takes a very long time to run. The planners update the model by removing some variables they consider less important than others. Of the following, which is the most likely effect the updated model will have on the simulation?

• The updated model is likely to decrease the runtime of the simulation because the time required for simulations generally depends on the complexity of the model used.

• The updated model is likely to decrease the runtime of the simulation because simulations that use older models tend to require more time to run than simulations that use newer models.

• The updated model is unlikely to decrease the runtime of the simulation because the simulation is computationally complex, regardless of the model used.

• The updated model is unlikely to provide any benefit because removing details from a model will compromise the accuracy of the simulation.

Which of the following statements describes a limitation of using a computer simulation to model a real-world object or system?

• Computer simulations can only be built after the real-world object or system has been created.

• Computer simulations only run on very powerful computers that are not available to the general public.

• Computer simulations usually make some simplifying assumptions about the real-world object or system being modeled.

• It is difficult to change input parameters or conditions when using computer simulations.

A population researcher is interested in predicting the number of births that will occur in a particular community. She created a computer model that uses data from the past ten years, including number of residents and the number of babies born. The model predicted that there would be 200 births last year, but the actual number of births last year was only 120. Which of the following strategies is LEAST likely to provide a more accurate prediction?

Responses

• Gathering data for additional years to try to identify patterns in birth rates

• Refining the model used in the computer simulation to more closely reflect the data from the past ten years

• Removing as many details from the model as possible so that calculations can be performed quickly

• Taking into consideration more information about the community, such as the ages of residents

A car manufacturer uses simulation software during the design process for a new car. Which of the following are reasons to use simulation software in this context?

1. Using simulation software can save the company money by helping to compare designs early in the process, before prototype cars are built.

2. Using simulation software can help to identify safety issues by providing data about how different mechanical components will interact in a wide variety of situations.

3. The manufacturer can present simulation software to customers to demonstrate different design possibilities.

• I and II only

• I and III only

• II and III only

• 
  I, II, and III