Understanding Compression Techniques Quiz

Which of the following is an example of a lossy compression method?

• JPEG

• ZIP

• PNG

• TAR

Answer explanation

JPEG is a lossy compression method, meaning it reduces file size by permanently eliminating some image data. In contrast, ZIP, PNG, and TAR are lossless methods, preserving all original data.

Which type of compression allows you to perfectly reconstruct the original data after decompression?

• Lossy compression

• Lossless compression

• Both lossy and lossless

• Neither

Answer explanation

Lossless compression allows for the exact reconstruction of original data after decompression, making it ideal for applications where data integrity is crucial. In contrast, lossy compression sacrifices some data for smaller file sizes.

Which of the following is a common application of lossy compression?

• Text document archiving

• Medical imaging

• Digital music files (MP3)

• Source code storage

Answer explanation

Digital music files (MP3) commonly use lossy compression to reduce file size while maintaining acceptable audio quality, making them ideal for streaming and storage. Other options like text and medical imaging require lossless compression.

Which of these is a type of lossless compression?

• MP3

• GIF

• JPEG

• MPEG

Answer explanation

GIF is a type of lossless compression, meaning it retains all original data without loss. In contrast, MP3, JPEG, and MPEG use lossy compression, which reduces file size by removing some data.

What is a main advantage of lossy compression?

• No data is lost

• Smaller file sizes

• Perfect quality retention

• Slower compression speed

Answer explanation

The main advantage of lossy compression is that it results in smaller file sizes, making storage and transmission more efficient. This is achieved by removing some data, which is not the case with lossless compression.

Which of the following is NOT a type of lossless compression?

• ZIP

• RAR

• MP3

• PNG

Answer explanation

MP3 is a lossy compression format used for audio, meaning it reduces file size by removing some audio data. In contrast, ZIP, RAR, and PNG are all lossless compression formats that preserve the original data without loss.

Which of these is an advantage of lossless compression?

• Smaller file size than lossy

• No loss of quality

• Data cannot be recovered

• Used for streaming videos

Answer explanation

Lossless compression retains all original data, ensuring no loss of quality, which is crucial for applications like text files and certain image formats. This is the primary advantage over lossy compression, which sacrifices quality for smaller file sizes.

Which of the following is most suitable for compressing photographs for use on a website?

• JPEG

• ZIP

• WAV

• TAR

Answer explanation

JPEG is the most suitable format for compressing photographs for websites due to its efficient compression and ability to maintain image quality. ZIP, WAV, and TAR are not ideal for images.

Which of these is a disadvantage of lossy compression?

• Larger file sizes

• Some data is permanently lost

• Slower to compress

• Cannot be used for images

Answer explanation

Lossy compression reduces file size by removing some data, which means that some data is permanently lost. This is a key disadvantage, as it can affect the quality of the compressed files, unlike lossless compression.

Which of the following is a typical use for lossless compression?

• Streaming movies

• Compressing text files

• Compressing music for portable players

• Reducing the size of photographs for social media

Answer explanation

Lossless compression is ideal for compressing text files because it preserves all original data, ensuring no information is lost. Other options like streaming movies or music often use lossy compression to save space.