Data Compression — Learn free

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Questions 1–10 of 10

1. What is data compression?
Question 1A. A method of encrypting files so they cannot be read without a keyB. A method of decreasing the size of files or data to save storage space and communication bandwidthC. A method of duplicating files across several serversD. A method of converting text files into imagesE. A method of deleting old files automatically
2. Why is data compression described as especially significant in the age of Big Data?
Question 2A. Because compressed data cannot be hackedB. Because Big Data is always structured and easy to storeC. Because unstructured data has a substantial influence on cloud storage costs, and neglecting compression means unnecessary expenditure and longer return-on-investment timelinesD. Because compression eliminates the need for cloud storage entirelyE. Because Big Data regulations require all files to be compressed
3. In text compression, how might the sentence 'The quick brown fox jumps over the lazy dog' be made smaller?
Question 3A. By storing each character in 16 bits instead of 8B. By translating the sentence into another languageC. By deleting every second wordD. By replacing commonly used words or phrases with shorter codes that are expanded again on decompressionE. By converting the text into an image
4. Which image compression format is named as achieving significant file size reduction while maintaining reasonable image quality?
Question 4A. JPEGB. MP3C. ZIPD. ASCIIE. RGB
5. How do audio compression algorithms such as MP3 reduce file size?
Question 5A. By increasing the sampling rate of the recordingB. By removing redundant or less perceptually important information, exploiting the fact that our ears are less sensitive to certain frequenciesC. By storing each note as a text descriptionD. By duplicating the audio track for redundancyE. By converting stereo sound into video
6. What distinguishes lossless compression from lossy compression?
Question 6A. Lossless compression always produces smaller files than lossy compressionB. Lossless compression is used only for audio; lossy only for textC. Lossless compression retains all the original data when decompressed, while lossy compression sacrifices some information for higher compression ratiosD. Lossy compression retains all data; lossless discards someE. There is no difference; the terms are interchangeable
7. Zipping a file and then unzipping it returns exactly the same file. Which kind of compression does this illustrate?
Question 7A. Lossy compressionB. Audio compressionC. Perceptual compressionD. Image compressionE. Lossless compression
8. In JPEG compression, some details in an image may be lost. What is the trade-off for this loss?
Question 8A. A much smaller file sizeB. Higher image resolutionC. Better colour accuracyD. Faster camera shutter speedE. Automatic backup of the original
9. How do streaming services make use of data compression?
Question 9A. To store user passwords more securelyB. To transmit audio and video efficiently so users can watch or listen without downloading huge filesC. To increase the number of adverts shownD. To convert video into text subtitlesE. To prevent users from pausing playback
10. Which of the following is NOT an example of data compression in use?
Question 10A. Downloading a ZIP file and unzipping it to restore the original filesB. Using JPEG to store a digital photographC. Using MP3 to store a music trackD. Storing each ASCII character of a text file at its full 8 bits without any encodingE. A streaming service transmitting a film efficiently