CodeHS Unit 8: Digital Information

Which of the following is a true statement about data compression?   

• Data compression is only useful for files being transmitted over the Internet.

• Regardless of the compression technique used, once a data file is compressed, it cannot be restored to its original state.

• Sending a compressed version of a file ensures that the contents of the file cannot be intercepted by an unauthorized user.

• There are trade-offs involved in choosing a compression technique for storing and transmitting data.

Ryan is designing an app that needs to quickly send low quality photos between users. Most smartphones take much higher quality photos than Ryan needs for his app. Which answer best describes the type of compression Ryan should choose and why?

• Lossy compression since it typically results in smaller data sizes.

• Lossless compression since it ensures perfect reconstruction of the photo.

• Lossy compression since it ensures perfect reconstruction of the photo.

• Lossless compression since it typically results in smaller data sizes.

What is the 4-bit binary number for the decimal number 10? 

• 0010

• 1010

• 0110

• 0101

How many numbers can be represented with an 8-bit binary system?

• 128

• 256

• 127

• 255

What is the difference between analog and digital signals?

• Analog signals are continuous and can take any value within a range, while digital signals are discrete and can only take specific values.

• Analog signals are more reliable than digital signals

• Analog signals are faster than digital signals

• Analog signals are only used for audio, while digital signals are only used for video

Discuss the importance of data compression in digital information.

• It increases storage space and slows down data transmission.

• It only works for analog information, not digital.

• It reduces storage space and allows for faster data transmission.

• It has no impact on storage space or data transmission speed.

Your computer uses 4 bits to represent decimal numbers (0, 1, 2, 3 and so on) in binary. What is the SMALLEST number for which an overflow error occur?

• 14

• 15

• 16

• 17

Which of the following best describes how computing devices represent information?

• A computer will either represent information as bits or bytes but not both

• A computer represents data as a byte which is either a 0 or a 1.

• A computer represents data as bits which is either a 0 or a 1.

• A computer represents information as bits which contain 8 bytes.

Which of the following can be represented by a sequence of bits?

I. An integer II. A character III. A sound wave   

• I only

• II only

• I and II only

• I, II, and III

Explain the concept of encoding and decoding in the context of digital information.

• Encoding is the process of converting data into audio files, while decoding is the process of converting audio files into text.

• Encoding is the process of compressing data to save storage space, while decoding is the process of expanding the data back to its original size.

• Encoding is the process of converting data into a specific format for transmission or storage, while decoding is the process of converting the encoded data back into its original form.

• Encoding is the process of encrypting data for security, while decoding is the process of decrypting the data to make it readable.