Digital Data Unit 2
What is the range of values (expressed in decimal) that each color channel can have?
0 to 255
Approximately how much bigger is a megabyte than a kilobyte?
1,000 times bigger
What is the value of 9F16 in binary?
1001 1111
Consider the following numbers: The decimal value 10 base 10 The binary value 1001 base 2 Hexadecimal value C base 16 Which of the following lists the number in order from least to greatest?
1001 base 2, 10 base 10, C base 16
What is the decimal value of 1101 base 2?
13
What is the largest value you can represent using 4 bits?
15
What is the value of F16 in decimal?
15 base 10
How many different symbols can be used for one digit in the Hexadecimal number system?
16
What is the number base of the binary number system?
2
Suppose the ESPN website uses 8-bit unsigned integers to store how many points a team has scored in an NBA game. For example: 0000 0010 represents 2 points 0000 1000 represents 8 points What is the highest possible score (in decimal) the ESPN website could display?
255
A news website uses 32-bit integers to count the number of times an article has been viewed. The website is becoming more popular, and expects some of the articles to exceed the number of views that can be represented with 32 bits. In anticipation of this, the website is planning to change to 64-bit integers for the view 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
Alice has 600 MB of data. Bob has 2000 MB of data. What is the smallest size drive in GB that will be able to hold all of Alice's and Bob's data?
3GB
How many possible values can be created with only 2 bits?
4
Ms. Wristers has 150 small images, each of which is 500 KB. How much space do they take up overall in MB?
75MB
How many bits make a byte?
8
How many bits are used to encode a character according to the ASCII encoding scheme?
8 bits
What is a pixel?
A single tiny dot, or square, of color in a digital image.
A computer program uses 3 bits to represent integers. When the program adds the decimal (base 10) numbers 6 and 2, the result is 0. Which of the following is the best explanation for this result?
An overflow error occurred
Which number system is used to store information digitally in a computer?
Binary (base 2)
Which choice below would make the color represented by #F897BD a darker color?
F800BD
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
Which of the following is true about lossy compression?
Lossy compression can compress data down to significantly less bits than lossless compression can. Data compressed with lossy compression cannot be restored back to its original state. Lossy compression throws away a lot of the original data, but humans can't even tell anything is missing.
What is the best term for this type of "data about the data"?
Metadata
What are the 3 color channels that make up a pixel according to the RGB color scheme?
Red, Green, Blue
Which of the following are examples of encoding information?
Representing fast food meals as numbers on the menu. For example a number 1 represents a hamburger. Assigning a numeric value to every area of a region, for example zip codes in the United States Assigning a number to every character of the alphabet so we can represent sentences as series of simple digits.
Which of the following is true about lossless data compression?
The compressed data can be restored back to its original state
What is data abstraction?
The process of simplifying complicated data into manageable chunks
A student is transferring photos from her camera to her computer. The student notices that the saved photos on her computer are lower quality than the original raw photo on her camera. Which of the following could be a possible explanation for the difference in image quality?
The saved image files were compressed with a lossy compression technique.
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.
Why do we compress data?
To save memory space on devices. To speed up the time it takes to send a file over the internet. The computation it takes to decompress data is cheaper than the storage space required to store uncompressed data.
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 reasonable time and an approximate solution is acceptable
Which of the following pixels has a color value of #ff0000 (expressed in hexadecimal)
a red pixel
ZIP
compressed files - lossless
PNG
compressed image - lossless
GIF
compressed image - lossless (256 color limit)
JPEG
compressed image - lossy
MP3
compressed sound - lossy
The salesperson in a cell phone store is telling me that the phone I'm considering has 8GB of memory, which means I can save 10,000 photos taken with the phone's camera. Is this true or false?
false
Select the answer that lists the units of bytes in ascending order (from smallest to largest)
kilobyte, gigabyte, terabyte
BMP
uncompressed image
WAV
uncompressed sound
