AP CSP
Choose the answer that is NOT a feature of Public Key Cryptography:
A Public Key database ensures 3rd party accountability of security
8 bits is enough to represent 256 different numbers. How many total bits do you need to represent 512 (twice as many) numbers?
9 bits
The various protocols in use of the Internet are said to operate in layers in which the protocol(s) at each layer solve one problem related to networked communication, and higher layers are built on top of and rely on the lower layers to do their jobs. From the list provided, choose the two (2) answers that correctly describe which internet protocol relies on the other. For example: if protocol A relies on protocol B, it means that A is a higher level protocol than B, and thus protocol B must exist and work properly in order for protocol A to do its job. Select two answers.
*HTTP relies on TCP/IP *DNS relies on TCP/IP
This question refers to the same data from the High School Survey about college plans from the previous question. Amara plans to use the survey data to create a visualization and short write up about students' plan for college, but first she wants to learn more about how the survey was conducted. Of the following things she might learn about the survey, which are the most likely sources of bias in the results based on how it was collected? Choose two answers
*She learns that responses were collected only by mobile app *She learns what the survey was only available to student who scored at the top 10% on the PSAT
Consider the following 3 binary numbers: 01000 , 010000, 11110. Which of the following lists the numbers in order from least to greatest?
01010, 010000, 11110
Approximately how much bigger (how many more bytes) is a megabyte than a kilobyte?
1,000 times bigger
What is the 4-bit binary number for the decimal number Ten (10)? *
1010
A video-streaming Web site uses 32-bit integers to count the number of times each video has been played. In anticipation of some videos being played more times than can be represented with 32 bits, the Web site is planning to change to 64-bit integers for the counter. Which of the following best describes the result of using 64-bit integers instead of 32-bit integers?
2^32 times as many values can be represented
Two students have developed a protocol in which they send 4-bit messages to each other. They decide to modify their protocol to start sending 8-bit messages instead. How many more values can be represented in an 8-bit message than in a 4-bit message?
2^4 16 times as many values
What is the minimum number of bits you would need to encode the 26 letters of the alphabet plus a space - a total of 27 characters? *
3 bits
The world is currently in a transition to using IPv6, a new version of the IP protocol that uses 128-bit addresses instead of 32-bit addresses uses by IPv4. What is the main problem that IPv6 was created to solve.
32-bit addresses could not ensure that every internet-connected device can receive a unique IP address
Pick the two expressions involving the Modulo operation that compute to the exact same value (choose 2)
9 MOD 8 1 MOD 16
The Internet Engineering Task Force (IETF) defines the protocols and standards for how the Internet works. The members of the IETF are:
A loosely organized collection of citizens and engineers
Which of the following statements are true about routers and routing on the Internet. Choose two answers.
A packet traveling between two computers on the Internet may be rerouted many times along the way or even lost or "dropped" Routers act independently and route packets as they see fit
Which of the following BEST describes how protocols on the Internet (e.g. IP, TCP, HTTP) make use of abstraction to accomplish their respective purposes?
Low level protocols can provide functionality to high level protocols without revealing the details of how this is accomplished
Which of the following most accurately describes Moore's Law? *
Moore's Law is the observation taht computing power tends to double every two year
ASCII is a character-encoding scheme that uses a numeric value to represent each character. For example, the uppercase letter "G" is represented by the decimal (base 10) value 71. A partial list of characters and their corresponding ASCII values are shown in the table below. ASCII characters can also be represented by binary numbers. According to ASCII character encoding, which of the following letters is represented by the 8-bit binary value: 0100 0010 *
ASCII Character B
A middle school is expanding to open a high school this year, doubling the amount of total students. The school keeps a database in which each student's each unique ID number is stored as an 8 bit number called studentID. Before the arrival of the new students almost every 8 bit number has already been assigned to a student. Of the options provided below, which is the smallest degree of change to the way studentID is represented necessary to ensure each incoming student receives a unique ID? *
Add a bit to studentID to double the number of IDs that the database can represent
What is a Distributed Denial of Service (DDoS) attack?
An attempt to compromise a single target by flooding it with requests from multiple systems.
Fill in the blank of the following statement:"______ encryption is a method of encryption involving one key for both encryption and decryption."
Asymmetric
This question refers to the same data from the High School Survey about college plans from the previous question. Amara decides to make a visualization of a portion of the responses showing only a few states and a few areas of study. She wants to make an effective visualization that shows for comparison: Students average likelihood of attending college in-state broken down by which state they live in and what they plan to major it. For example, in Illinois (IL) on average students who want to study economics are very likely to say they want to attend college in-state. Amara makes four different visualizations shown below, marked A, B, C, D. According to good principles of visualization, and for what Amara wants to show, which one of these would be considered the best visual representation?
B
The figure represents a network of physically linked computers labeled A through F. A line between two computers indicates that the computers can communicate directly with each other. Any information sent between two computers that are not directed connected must go through at least one other computer. The weight or cost of sending information from one computer to another is indicated by the number above the line. For example, information can be sent directly between computers A and B and will cost 5. Information sent between computers A and D must go through either computer C (with total cost 5), or through computer B (with total cost 8). Computer A sends a packet intended to reach Computer F. Along its path it arrives at Computer C. Which computer should Computer C forward the packet to in order to uses the most cost effective path? * 1/1
Computer D
Consider the following numbers given in Binary (BIN), Decimal (DEC), and Hexadecimal (HEX) representations:BIN: 1110DEC: 13HEX: F Which of the following lists the numbers in order from least to greatest?
DEC: 13 BIN: 1110 HEX: F
Biologists often attach tracking collars to wild animals. For each animal, the following geolocation data is collected at frequent intervals. *The time *The date *The location of the animal Which of the following questions about a particular animal could NOT be answered using only the data collected from the tracking collars
Do the movement patterns of theanimal vary accoding to the weather?
An artist makes an RGB raster image in which each pixel color is encoded with 12 bits - 4 bits each for red, green and blue. Which of the following correctly shows the hexadecimal value for Red as a 12-bit representation.
F00
The chart from Google Trends shows the prevalence of some search terms in the US between 2004 and the present. Which of the following is the most accurate statement of what this chart is showing.
Generally speaking, since 2009 more people use "red" in their search terms more than they use "blue", "yellow", "green", or "purple"
A raw digital sound file samples a sound wave at some interval and measures the height of the wave at each point. Thus, raw sound is recorded as a list of numbers. In very broad terms the MP3 audio compression algorithm identifies frequencies and volume levels - low and high - that are outside the range of human hearing and removes the data representing these frequencies from the original. This technique results in a smaller audio file that sounds exactly the same to the human ear. This technique is an example of what type of compression.
Lossy compression
How does a computer resolve a domain name into an IP address? *
It asks a DNS server for the corresponding IP address
What is the best explanation for why digital data is represented in computers in binary? *
It's easier, cheaper, and more reliable to build machines and devices that only have to distinguish between 2 binary states
A compression scheme for long strings of bits called run-length encoding is described as follows: Rather than record each 0 and 1 individually, instead record "runs" of bits by storing the number of consecutive 1s and 0s that appear. Since it's binary, any run of 0s must be followed by a run of 1s (even if the run is only 1-bit long) and vice versa. Thus, you can store a list of small numbers that represents the alternating runs of 0s and 1s. See the example: To uncompress the data back into its original binary state, you simply reverse the process. This technique is an example of what type of compression?
Lossless compression
The colors of the pixels in a digital image are often represented by red, green, and blue values between 0 and 255 (an RGB triplet). A photographer is manipulating a digital image to lighten it because all of the RGB values in the image are less than 100, making it very dark. He does this by adding 20 to the R, G, and B values of each pixel, then overwriting the original image. What type of transformation is the photographer using on the digital image? *
Lossless transformation
A user clicks on a website, and it begins to load immediately, but it takes a long time to load completely and pictures appear slowly, one by one. Which of the following is demonstrated through this situation? *
Low bandwidth, low latency
Which of the following statements best describes the properties of public key encryption?
Public Key encryption is an encryption method which relies on separate keys for encrypting and decryption information.
The next three questions all refer to data collected an a hypothetical survey of high school seniors, and a student, Amara, who is working with the data. The survey of high school seniors asked: What state do you live in? How likely are you to attend college in your home state? (on a scale of 1-5; 5 meaning "very likely" and What do you plan to study? Amara does an initial computation on the data to make a summary table. A small segment is shown here. Amara is tasked with cleaning the data to prepare it for further analysis. Which of the following would be the least appropriate modifications to make to the data to prepare it for further analysis?
Round up all non-integer values for "Likelihood of staying in state"
The AP CS Principles framework contains the following statement: 7.1.1G Search trends are predictors. Which of the following is the most accurate statement about using search trends as predictors of future events? *
Search trends are imperfect predictors of future events that may not fully represent society at large
Which of the following is NOT true about TCP/IP packets? *
TCP guarantees that no packets are ever dropped
Under which of the following conditions is it most beneficial to use a heuristic approach to solve a problem? *
When the problem cannot be solved in a resaonable time and an approximate solution is acceptable
The image below shows an encoding for a black and white pixel image. The first two bytes of data (circled in red) are used to encode the width and height of the image. What is the best term for this type of "data about the data"? *
metadata
A programmer is writing a system that is intended to be able to store large amounts of personal data. as the programmer develops the data system, which of the following is LEAST likely to impact the programmer's choices in designing the structure of the system
The frequency of a particular item occurring in a data set
A programmer is writing a system that is intended to be able to store a large amounts of personal data. As the programmer develops the data system, which of the following is LEAST likely to impact the programmer's choice in designing the structure of the system?
The frequency of a particular item occurring in a data set.
Which of the following is a true statement about data compression? *
There are trade-offs involved in choosing a compression technique for storing and transmitting data
A certain social media Web site allows users to post messages and to comment on other messages that have been posted. When a user posts a message, the message itself is considered data. In addition to the data, the site stores the following meta data. *The time the message was posted * The name of the user who posted the message *The names of any users who comment on the message and the times the comments were made For which of the following goals would it be more useful to analyze the data instead of the metadata?
To determine the topics that many users are posting about
Number systems with different bases such as binary (base-2), octal (base-8), decimal (base-10), and hexadecimal (base-16) are all used to view and represent visual data. Which of the following are NOT true about representing digital data? *
When data is large enough, computers switch to using digital representation instead of binary, because you can represent larger numbers with fewer digits
A school starts tracking which websites each computer in the school is visiting by monitoring the packets leaving the school. A sample of the information they have collected appears below: Which of the following is MOST likely to be answerable using all the data collected by this monitoring? *
Which websites are most frequently visited before and after school hours from a school computer
A coffee shop is considering accepting orders and payments through their phone app and have decided to use public key encryption to encrypt their customers' credit card information. Is this a secure form of payment?
Yes, public key encryption is built upon computationally hard problems that even powerful computers cannot solve easily.
Which of the following scenarios is most characteristic of a phishing attack.
You get an email from the IT support desk that asks you to send a reply email with your username and password to verify your account
According to the domain name system (DNS), which of the following is a subdomain of the domain example.com? *
about.example.com
Select the answer that lists the units of bytes in ascending order (from smallest to largest)
kilobyte, gigabyte, terabyte
Which of the following are true statements about digital certificates in Web browsers? I. Digital certificates are used to verify the ownership of encrypted keys used in secured communication II. Digital certificates are used to verify that the connection to a Web site is fault tolerant.
l only
