Years 9–10 Data & Information Crossword: Data compression (Modules 6–16)
Name:
Date:
Class:
✎
Crossword
Read each clue and write the matching term in the grid. Numbers in brackets show the letters in each word.
1
2
3
4
5
6
7
8
9
10
Across
- 1. Give each repeated word or phrase a short code, store the code table once, then replace every repeat with its code so the data takes up fewer characters. Word 1 of: __________ ___________ (10)
- 4. Word 4 of the term in 3 Down: ___________ _____ = ________ ____ / compressed ____ (4)
- 6. 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. (10)
- 8. 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. Word 1 of: _____ ___________ (5)
- 9. Word 2 of the term in 3 Down: ___________ _____ = ________ ____ / compressed ____ (5)
- 10. Word 3 of the term in 7 Down: ________-length ______ (6)
Down
- 2. 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. Word 2 of: lossless ___________ (11)
- 3. ______ ______ divided by compressed ______. Percentage saved = (______ - compressed) / ______ x 100. Example: 10 MB down to 2 MB is a ______ of 5 to 1, saving 80%. Word 3 of: ___________ _____ = ________ ____ / compressed ____ (8)
- 5. 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. Word 2 of: RLE _________ (9)
- 7. 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. Word 1 of: ________-length ______ (8)
Answer Key
Years 9–10 Data & Information · Modules 6–16
1D
I
2C
T
I
3O
N
A
R
Y
O
R
M
4S
I
Z
5E
P
G
X
R
I
P
6R
E
D
U
N
D
A
N
C
Y
7V
S
A
N
A
S
8L
O
S
S
Y
9R
A
T
I
O
I
I
O
10C
O
D
I
N
G
A
N
N
B
L
E
Across
1DICTIONARY — Give each repeated word or phrase a short code, store the code table once, then replace every repeat with its code so the data takes up fewer characters. Word 1 of: __________ ___________
4SIZE — Word 4 of the term in 3 Down: ___________ _____ = ________ ____ / compressed ____
6REDUNDANCY — 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.
8LOSSY — 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. Word 1 of: _____ ___________
9RATIO — Word 2 of the term in 3 Down: ___________ _____ = ________ ____ / compressed ____
10CODING — Word 3 of the term in 7 Down: ________-length ______
Down
2COMPRESSION — 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. Word 2 of: lossless ___________
3ORIGINAL — ______ ______ divided by compressed ______. Percentage saved = (______ - compressed) / ______ x 100. Example: 10 MB down to 2 MB is a ______ of 5 to 1, saving 80%. Word 3 of: ___________ _____ = ________ ____ / compressed ____
5EXPANSION — 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. Word 2 of: RLE _________
7VARIABLE — 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. Word 1 of: ________-length ______