Years 9–10 Data & Information Word Scramble: Data compression (Modules 6–16)
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Word scramble
Unscramble the letters and write each key term on the line.
1
NEYCDRDUAN
Repeated or predictable data, like a run of the same letter or colour, that can be stored in a shorter form without losing any information.
2
SSSLOESL NCOEPOSMSIR
Shrinks a file so the exact original data can be rebuilt perfectly, with nothing lost. ZIP and PNG use it. Needed for text and programs.
3
OYSLS MPNSIRSCOOE
Shrinks a file by permanently throwing away detail people are unlikely to notice, so the original can't be rebuilt exactly. JPEG and MP3 use it.
4
3A4B
Run-length encoding: each run of identical characters becomes a count then the character, so AAAABBB is written ______. A single character is written 1X.
5
D2C3 = DDCCC
Decoding run-length data: read each count then its character, and write that character that many times. 3C means CCC and 2D means DD, so 3C2D expands back to CCCDD.
6
LNT-NRUHEG NGDOCEIN
Compress a black-and-white image by writing each row as counts of same-coloured pixels in a run, starting with white. Row 00000 111 00 becomes 5,3,2. Counts can rebuild the grid.
7
ELR NXPAEOSNI
When data has few repeats, run-length encoding adds a count to every character, so the result can be longer than the original. It only saves space when the data has long runs.
8
LERAAHIB-EVTNGL DCIONG
Gives common characters short bit codes and rare ones longer codes, so a whole message uses fewer bits than if every character used the same fixed number of bits.
Answer Key
Years 9–10 Data & Information · Modules 6–16
1NEYCDRDUAN → redundancy — Repeated or predictable data, like a run of the same letter or colour, that can be stored in a shorter form without losing any information.
2SSSLOESL NCOEPOSMSIR → lossless compression — Shrinks a file so the exact original data can be rebuilt perfectly, with nothing lost. ZIP and PNG use it. Needed for text and programs.
3OYSLS MPNSIRSCOOE → lossy compression — Shrinks a file by permanently throwing away detail people are unlikely to notice, so the original can't be rebuilt exactly. JPEG and MP3 use it.
43A4B → 4A3B — Run-length encoding: each run of identical characters becomes a count then the character, so AAAABBB is written 4A3B. A single character is written 1X.
5D2C3 = DDCCC → 3C2D = CCCDD — Decoding run-length data: read each count then its character, and write that character that many times. 3C means CCC and 2D means DD, so 3C2D expands back to CCCDD.
6LNT-NRUHEG NGDOCEIN → run-length encoding — Compress a black-and-white image by writing each row as counts of same-coloured pixels in a run, starting with white. Row 00000 111 00 becomes 5,3,2. Counts can rebuild the grid.
7ELR NXPAEOSNI → RLE expansion — When data has few repeats, run-length encoding adds a count to every character, so the result can be longer than the original. It only saves space when the data has long runs.
8LERAAHIB-EVTNGL DCIONG → variable-length coding — Gives common characters short bit codes and rare ones longer codes, so a whole message uses fewer bits than if every character used the same fixed number of bits.