Data compression unit 1 Mcq
1. Data compression means to ______ the file size.
(A) Increase
(B) Decrease
(C) Can't say
(D) None of the above
2. Data compression and encryption both work on binary code.
(A) False
(B) True
3. What is compression?
(A) To compress something by pressing it very hardly
(B) To minimize the time taken for a file to be downloaded
(C) To reduce the size of data to save space
(D) To convert one file to another
4. Data compression usually works by _______.
(A) Deleting random bits data
(B) Finding repeating patterns
5. Why data compressed?
(A) To optimise the data
(B) To reduce secondary storage space
(C) To reduce packet congestion on networks
(D) Both (B) and (C)
6. Which is a type of data compression?
(A) Resolution
(B) Zipping
(C) Inputting
(D) Caching
7. Data compression involves
(A) Compression only
(B) Reconstruction only
(C) Both compression and reconstruction
(D) None of the above
8. Based on the requirements of reconstruction, data compression schemes can be divided into ____ broad classes.
(A) 3
(B) 4
(C) 2
(D) 5
9. _______ compression is the method which eliminate the data which is not noticeable and _______ compression does not eliminate the data which is not noticeable.
(A) Lossless, lossy
(B) Lossy, lossless
(C) None of these
10. ______ compression is generally used for applications that cannot tolerate any difference between the original and reconstructed data.
(A) Lossy
(B) Lossless
(C) Both
(D) None of these
11. What is compression ratio?
(A) The ratio of the number of bits required to represent the data before compression to the number of bits required to represent the data after compression.
(B) The ratio of the number of bits required to represent the data after compression to the number of bits required to represent the data before compression.
(C) The ratio of the number of bits required to represent the data after reconstruction to the number of bits required to represent the data before compression.
(D) The ratio of the number of bits required to represent the data before reconstruction to the number of bits required to represent the data after reconstruction.
12. Suppose storing an image made up of a square array of 256×256 pixels requires 65,536 bytes. The image is compressed and the compressed version requires 16,384 bytes. Then compression ratio is _______.
(A) 1:4
(B) 4:1
(C) 1:2
(D) 2:1
13. Lossy techniques are generally used for the compression of data that originate as analog signals, such as
(A) Speech
(B) Video
(C) Both
(D) None of these
14. If fidelity or quality of a reconstruction is _____, then the difference between the reconstruction and the original is ______.
(A) High, small
(B) Small, small
(C) High, high
(D) None of the above
15. The development of data compression algorithms for a variety of data can be divided into ____ phases.
(A) 2
(B) 3
(C) 4
(D) 5
16. Which of the following is true of lossy and lossless compression techniques?
(A) Lossless compression is only used in situations where lossy compression techniques can't be used
(B) Lossy compression is best suited for situations where some loss of detail is tolerable, especially if it will not be detectable by a human
(C) Both lossy and lossless compression techniques will result in some information being lost from the original file
(D) Neither lossy nor lossless compression can actually reduce the number of bits needed to represent a file
17. Which of the following would not be suitable for Lossy Compression?
(A) Speech
(B) Video
(C) Text
(D) Image
18. Which of the following are not in a compressed format?
(A) MP3
(B) Bitmap
(C) MPEG
(D) JPEG
19. Information theory was given by
(A) Claude von Regan
(B) Claude Elwood Shannon
(C) Claude Monet
(D) Claude Debussy
20. The unit of information depends on the base of the log. If we use log base 2, the unit is ____; if we use log base e, the unit is ____; and if we use log base 10, the unit is _____.
(A) Hartleys, nats, bits
(B) Hartleys, bits, nats
(C) Bits, nats, hartleys
(D) Bits, hartleys, nats
21. According to Claude Elwood Shannon's second theorem, it is not feasible to transmit information over the channel with ______ error probability, although by using any coding technique.
(A) Large
(B) May be large or small
(C) Unpredictable
(D) Small
22. The essential condition/s for a good error control coding technique?
(A) Better error correcting capability
(B) Maximum transfer of information in bits/sec
(C) Faster coding & decoding methods
(D) All of the above
23. The prefix code is also called as
(A) Block code
(B) Convolutional code
(C) Parity code
(D) Instantaneous code
24. Self information should be _____.
(A) Negative
(B) Positive
(C) Both
(D) None of these
25. A code in which no codeword is a prefix to another codeword is called as
(A) Prefix cod
(B) Parity code
(C) Convolutional code
(D) Block code
26. The set of binary sequences is called a _____, and the individual members of the set are called _______.
(A) Codewords, code
(B) Code, codewords
(C) None of these
27. Full form of ASCII.
(A) American Standard Code for Information Intercaste
(B) American Standard Codewords for Information Interchange
(C) American Standard Code for Information Interchange
(D) American System Code for Information Interchange
28. Composite source models is a combination or composition of several sources. In which how many source being active at any given time?
(A) All
(B) Only one
(C) Only the first three
(D) None of these
Correct option is B
29. For models used in lossless compression, we use a specific type of Markov process called a
(A) Continous time Markov chain
(B) Discrete-time Markov chain
(C) Constant time Markov chain
(D) None of the above
30. Markov model is often used when developing coding algorithms for
(A) Speech
(B) Image
(C) Both
(D) None of these