AP CSP - Data Compression

A student is recording a song on her computer. When the recording is finished, she saves a copy on her computer. The student notices that the saved copy is of lower sound quality than the original recording. Which of the following could be a possible explanation for the difference in sound quality?

• The song was saved using fewer bits per second than the original song.

• The song was saved using more bits per second than the original song.

• The song was saved using a lossless compression technique.

• Some information is lost every time a file is saved from one location on a computer to another location.

What is abstraction?

• Making a photo smaller but more pixelated
• Hiding the complexity with something simpler

When visiting a museum Sue takes a photo of a painting with a smartphone which stores the photo as an image file. Which of the following best describes the differences between the painting itself and the photo of the painting stored on the smartphone?

• Both the painting and the photo are analog

• Sampling can be used to determine whether the analog image is an accurate representation of the painting

• The phone can represent the photo in either digital or analog formats depending on the sampling technique that is used

• The photo is a digital representation of the analog painting

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.

Elijah, Abigail, and Luna are on a mission to save their digital world. They need to convert some analog data into digital. What is this process called?

• Sampling

• Binary

• Data Compression

• Decimal

Which of the following is a reason to use lossy compression?

• You want the compressed file to be larger than the original.

• You want the highest quality audio file possible, with no modifications.

• You want the highest quality image file possible, with no modifications.

• You want to save space and are not concerned if the file is the highest quality possible.

Which of the file types is an audiofile type?

• jpg

• mp3

• png

• csv

An original file is 100 MB, it is compressed to 80 MB (including dictionary). What is its compression rate?

• 90%

• 80%

• 20%

• 100%

Values that change smoothly, rather than in discrete intervals, over time. For example, the pitch and volume of a live concert.

• analog data

• digital data

• metadata

• data

Compressing data in a way that discards some data and makes it impossible to recover the original.

• lossless

• lossy

• graphical

• dataless