AP Computer Science Principles Unit 2: Big Idea 2: Data Practice Exam

Assessment for Unit 2: Big Idea 2: Data

Estimated Time: 60 minutes

Exam Details

Questions: 20 total (20 multiple choice)
Time: 60 minutes (recommended)
Topics Covered: Unit 2: Big Idea 2: Data
Format: Multiple Choice questions matching real exam difficulty
Scoring: Instant results with detailed explanations

A. Multiple-Choice Questions (20 Questions)

Select the one best answer for each question.

1. All digital data, including text, images, and sounds, are ultimately represented in a computer as sequences of which of the following?

2. What is the decimal (base 10) equivalent of the binary (base 2) number 1101?

(A)9(B)11(C)13(D)15

3. A computer uses 4 bits to represent positive integers. If a program attempts to store the decimal value 17, which of the following is the most likely result?

(A)The number is stored correctly as 10001.(B)A round-off error occurs, storing the closest possible value.(C)An overflow error occurs because the number is too large to be represented.(D)The computer automatically uses a different encoding scheme to store the number.

4. The process of using a specific sequence of bits to represent a character like 'A', or a group of bits to represent the color red in a pixel, is an example of which of the following computational concepts?

(A)Data compression(B)Abstraction(C)Algorithm(D)Heuristic

5. A web developer is choosing a compression format for a website's main background image, which features a photograph with many subtle color gradients. The primary goal is to make the website load as quickly as possible, even if it means a slight, imperceptible loss of image detail. Which type of compression would be most appropriate?

(A)Lossless, because it guarantees the image will look exactly as the photographer intended.(B)Lossy, because it typically achieves a much smaller file size by discarding non-essential data.(C)No compression, to ensure the highest possible quality for all viewers.(D)Lossless, because it is better at handling images with many different colors.

6. A legal firm needs to archive digital copies of signed contracts. The absolute highest priority is ensuring that the archived files are perfect, bit-for-bit copies of the originals, so that they can be legally verified if needed. Which of the following is the most appropriate strategy for storing these documents?

(A)Using a lossy compression algorithm to save storage space.(B)Using a lossless compression algorithm to reduce file size without losing any data.(C)Storing the documents without any compression to avoid data loss.(D)Using a heuristic algorithm to decide which parts of the documents are least important.

7. A photographer takes a digital picture. Along with the image itself, the camera file stores the date the photo was taken, the GPS coordinates of the location, and the camera settings used. This additional information is best described as which of the following?

(A)The data(B)The information(C)The metadata(D)The compression algorithm

8. A data scientist analyzes a large dataset from a city and discovers that ice cream sales are highest on days when the number of drownings is also highest. Concluding that buying ice cream causes people to drown is an error in reasoning because the data shows a correlation, not necessarily a causal relationship. What is a more likely explanation for this correlation?

(A)The data is biased and was collected improperly.(B)A third variable, such as high temperatures, is likely the cause of both increased ice cream sales and more people swimming.(C)There is not enough data to draw any conclusion.(D)The analysis software must have a bug that is creating a false pattern.

9. The teacher wants to calculate the average number of hours studied. Which of the following describes a data cleaning task that must be performed before this calculation can be completed?

(A)Removing the record for StudentID 103 because the quiz was submitted late.(B)Converting the value "two" in the "HoursStudied" column to the numerical value 2.(C)Deleting the "SubmittedOnTime" column as it is not needed for the calculation.(D)Adding more student records to the dataset to ensure accuracy.

10. Based on the data in the table, which of the following patterns can be observed?

(A)Students who submit their quiz on time always score higher than those who do not.(B)There is a positive correlation between the hours a student studied and their quiz score.(C)Every student who studied for 4 or more hours scored above 90.(D)No student who studied for less than 2 hours passed the quiz.

11. Which of the following describes how a program could be used to gain the insight that students who studied more tended to get higher scores?

(A)By creating a visualization, such as a scatter plot, with "HoursStudied" on one axis and "QuizScore" on the other.(B)By deleting all rows where the "SubmittedOnTime" value is "no".(C)By sorting the table by "StudentID".(D)By calculating the total number of students in the dataset.

12. What value is displayed as a result of running the algorithm on the tempReadings list?

(A)2(B)3(C)4(D)7

13. Which of the following best describes the overall purpose of this algorithm?

(A)It calculates the average temperature for the week.(B)It finds the highest temperature in the list.(C)It counts the number of days the temperature was above a certain threshold.(D)It creates a new list containing only the temperatures above 70.

14. How could the algorithm be modified to count the number of days the temperature was 70 degrees or colder?

15. A sound engineer is converting a recording of a live concert from an analog format to a digital format. The process involves measuring the amplitude of the sound wave at very frequent, regular intervals and recording each measurement as a number. This process is known as:

(A)Compressing(B)Encrypting(C)Sampling(D)Traversing

16. Many programming languages use a fixed number of bits, such as 32 or 64, to represent integers. Which of the following is a direct consequence of this fixed-size representation?

(A)It is impossible to represent the number 0.(B)All integer calculations are completely free of errors.(C)There is a limit to the largest integer value that can be stored, which can lead to overflow errors.(D)Real numbers with decimal points cannot be stored.

17. A research team is combining two large datasets of customer information from two different companies. One dataset lists the state as a two-letter abbreviation (e.g., "CA", "NY"), while the other writes out the full state name (e.g., "California", "New York"). This issue is an example of which data processing challenge?

(A)The need to clean data to make it uniform.(B)The presence of biased data.(C)The need for parallel systems.(D)The problem of incomplete data.

18. A program is designed to process a list of product prices called priceList. The goal is to create a new list, finalPrices, that contains the original price plus a 10% tax for every item. Which of the following code segments correctly performs this transformation?

19. In one context, the 8-bit binary sequence 01000001 represents the decimal number 65. In another context, the same sequence represents the character 'A'. Which of the following statements best explains this?

(A)One of the representations must be incorrect; a binary sequence can only have one meaning.(B)The meaning of a given sequence of bits depends on the context and the encoding scheme used to interpret it.(C)The binary sequence for the character 'A' is an approximation of the number 65.(D)The number 65 is metadata for the character 'A'.

20. A programmer is analyzing a list of user ratings for a mobile app, where each rating is a number from 1 to 5. The programmer wants to gain insight into user satisfaction. Which of the following is NOT an example of a process that a program could use to transform this data into useful information or knowledge?

(A)Calculating the average rating to determine overall satisfaction.(B)(C)Filtering the data to see the ratings from only the most recent month to identify current trends.(D)Converting the entire list of numbers into a single binary string.

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