I learnt many valuable skills while taking this College Board Practice MC Exam, including:

  • Time management during the test (to not get stuck on any problem for too long)
  • Code analysis in segments
  • Analysis of logical proceedings as written in pseudocode or data tables

I did well on most of the code analysis questions but still got a few wrong due to inconsistent time management and rushing through certain problems.

On this MC, I earned a 59/66. My analytics are as follows:

After viewing my score, I checked the topic breakdowns to determine which big ideas I need to work on the most. My mistakes ranged over many of the big ideas, proving I am not significantly lacking in any one topic (I instead need to work on improving my overall test-taking strategies).

Finally, my topic breakdown includes which topics I need to work on the most. Based on the listings below, I need to work on crowdsourcing the most.

Mistakes and Corrections

Question 3

Q: Which of the following would be the best use of citizen science?

Selected: An experiment that requires all participants to be working in the same laboratory

Correct: An experiment that requires data measurements to be taken in many different locations

I got this question wrong because I did not understand what citizen science is. I now know that citizen science is the engagement of many groups of people from the public in a scientific study, which explains why an experiment with data measurements from varied locations is more representative of citizen science than if all participants are in one location.

Question 12

Q: A social media site allows users to send messages to each other. A group of researchers gathered user data for the first 10 years of the site’s existence. Some of the data are summarized in the table below, along with some of the company milestones.

The researchers noticed that the total number of registered users appears to be increasing at about a constant rate. If this pattern continues, which of the following best approximates the total number of registered users, in millions, in year 12 (two years after the last entry in the table) ?

Selected: 30.6

Correct: 31.2

I did not read the question thoroughly (I was rushing). I had read 11 years as opposed to 12 years. In the future, I will make sure to slow down, even (especially) on problems that seem intuitive.

Question 21

Q: The following question uses a robot in a grid of squares. The robot is represented by a triangle, which is initially facing right.

Which of the following code segments will move the robot to the gray square?

Selected:

Correct:

I got this question wrong because I did not slow down and think about right vs. left.

Question 30

Q: A video-streaming service maintains a database of information about its customers and the videos they have watched. The program below analyzes the data in the database and compares the number of viewers of science fiction videos to the number of viewers of videos of other genres. It uses the procedure Analysis{category} which returns the number of unique users who viewed videos of a given category in the past year. The Analysis procedure takes approximately 1 hour to return a result, regardless of the number of videos of the given genre. All other operations happen nearly instantaneously.

Selected: 4 Hours

Correct: 5 Hours

I did not realize that the first analysis of science fiction was also 1 hour of processing time. I only factored in the analysis within the for loop, but I need to remember to include any processing done in definition of variables as well.

Question 42

Q: Internet protocol version 4 (IPv4) represents each IP address as a 32-bit binary number. Internet protocol version 6 (IPv6) represents each IP address as a 128-bit binary number. Which of the following best describes the result of using 128-bit addresses instead of 32-bit addresses?

Selected: 2^4 times as many addresses are available.

Correct: 2^96 times as many addresses are available.

I got this question wrong because I did not do the math for the addresses. 2^128 / 2^32 = 2^96, which is the delta in addresses between IPV4 and IPV6.

Question 43

Q: An online retailer uses an algorithm to sort a list of n items by price. The table below shows the approximate number of steps the algorithm takes to sort lists of different sizes.

Based on the values in the table, which of the following best characterizes the algorithm for very large values of n?

Selected: The algorithm runs, but not in reasonable time.

Correct: The algorithm runs in reasonable time.

I should remember that just because the number of steps increases, the processing time does not necessarily have to increase. Since the pattern indicates a polynomial increase in steps, the algorithm will run in reasonable time.

Question 46

Q: A student wants to create an algorithm that can determine, given any program and program input, whether or not the program will go into an infinite loop for that input. The problem the student is attempting to solve is considered an undecidable problem. Which of the following is true?

Selected: It is possible to create an algorithm that will solve the problem for all programs and inputs, but the algorithm will not run in reasonable time.

Correct: It is not possible to create an algorithm that will solve the problem for all programs and inputs.

I now know that an undecidable problem is one that should give a “yes” or “no” answer, but yet no algorithm exists that can answer correctly on all inputs. Therefore, even with all the time in the world, the program will not run, rendering my answer incorrect.