Lossless Compression (Khan Academy) - AP Comput...

What are the two primary reasons we use data compression?

• To make files more secure and harder to hack

• To save storage space and increase transmission speed

• To improve the resolution of images and video

• To convert text files into executable programs

Briefly explain the strategy used to compress the "Pitter Patter" poem in the video.

Fill in the blank: In the poem example, repeated phrases are replaced with symbols which are then stored in a (a)   .

What happens if you try to compress a file using symbols for phrases that only appear once?

• The file becomes much smaller

• The file size will likely increase due to the overhead of the dictionary

• The file becomes corrupted and cannot be opened

• The compression algorithm will run faster

When calculating the total size of a compressed file, what must be included besides the compressed text itself?

• The original uncompressed file

• The software used to compress it

• The dictionary or key used to map symbols to phrases

• The file's metadata and creation date

What is the defining characteristic of lossless compression?

• It discards unnecessary data that humans can't perceive

• It can only be used for text files, not images

• The original data can be perfectly reconstructed from the compressed version

• It always reduces the file size by exactly 50%

Why is lossless compression essential for files like computer programs or text documents?

Fill in the blank: Finding the absolute best way to compress a file is difficult because there are many different (a)   to choose from.