AZSCI Math & Computational Thinking 3

Question 1

A student develops a computational model to simulate the spread of an invasive plant species. The model includes variables for growth rate, seed dispersal distance, and germination probability. When testing the model, the student notices that if the 'growth rate' variable is set to a value slightly above zero, the simulated population immediately crashes. Which of the following is the most likely cause of this edge case behavior?

Accepted Answer

The model lacks a variable for the plant's mortality rate, causing an imbalance at low growth rates.

Answer

In a population model, growth must be balanced by mortality. Without a death rate, any positive growth rate, no matter how small, should lead to population increase. An immediate crash at a low positive growth rate suggests a logical flaw where the population calculation becomes unstable or negative because there's no counteracting factor like mortality. The other options are less likely to cause an immediate crash under these specific conditions.

Question 2

A team of students is using a computational model to determine the optimal placement of wind turbines in a valley. Their model accounts for wind speed, topography, and turbine efficiency. After running hundreds of simulations, they find two potential layouts that produce nearly identical energy output. To decide between them, they introduce a new constraint: minimizing the 'flicker effect' on nearby homes. This iterative process of refining a model by adding new constraints or variables is an advanced application of which computational thinking practice?

Accepted Answer

Abstraction

Answer

Abstraction involves focusing on the important details while ignoring irrelevant ones. In this scenario, the students initially abstracted the problem to only include energy output. When that proved insufficient, they refined their model by removing a layer of abstraction and introducing a new, relevant detail (the 'flicker effect'). This process of refining what is included and excluded from a model is a key aspect of abstraction.

Question 3

When analyzing a large dataset of patient recovery times, a scientist uses an algorithm to group patients based on multiple variables (age, treatment type, pre-existing conditions). The algorithm identifies a small, unexpected cluster of patients with extremely fast recovery times, despite having risk factors that suggest a poor prognosis. Which of the following computational thinking skills is most critical for the next step of the scientific investigation?

Accepted Answer

Recognizing this anomaly as a pattern that warrants further, targeted investigation.

Answer

While other skills are important, the immediate next step is to recognize that this unexpected cluster is itself a pattern. The core of data analysis in science is not just finding expected correlations but also identifying and investigating anomalies. This specific, anomalous pattern could lead to a new discovery about treatment efficacy or patient genetics. The other options are subsequent or less relevant actions.

Question 4

A student is designing an algorithmic model to predict the final temperature of a mixture of two liquids. The model works perfectly for most inputs. However, when the mass of one liquid is entered as zero, the program crashes due to a 'division by zero' error. Which computational thinking practice has been insufficiently applied, leading to this failure?

Accepted Answer

Testing and Debugging

Answer

This scenario describes a classic 'edge case' bug. A crucial part of Testing and Debugging is not just testing with typical values, but also testing with extreme or unusual inputs (like zero, negative numbers, or very large numbers) to ensure the algorithm is robust. The failure to anticipate and handle the 'zero mass' input demonstrates an incomplete testing and debugging process.

Question 5

A biologist is modeling the complex interactions within a forest ecosystem, including predator-prey relationships, plant competition for sunlight, and the role of decomposers. To make the model computationally feasible, they represent each species with a set of simplified rules for behavior (e.g., 'if fox is near rabbit, fox moves toward rabbit'). This technique of representing complex real-world entities with simplified, rule-based agents is a hallmark of:

Accepted Answer

Agent-based modeling

Answer

Agent-based modeling (ABM) is a computational method that simulates the actions and interactions of autonomous agents (both individual and collective entities such as organizations or groups) to assess their effects on the system as a whole. Representing each species as an 'agent' with simple rules that lead to complex emergent behavior is the defining characteristic of ABM.

(AZSCI) Arizona Science Test Practice Test

(AZSCI) Arizona Science Test Practice Test

AZSCI Math & Computational Thinking 3