Cit2 Exer Ans

Data and Information P.1 of 4 Class 4 (

) Name:____________________________ (

)

Part A: New Style Multiple Choice Questions: Complete the followings with WORDS/SENTENCES provided in P.43 to P.45 of your text. 1. Information is data after processing 2. The lowest level of data is Character 3. A key field is Used to identify records 4. The following input device is associated with transcription error keyboard 5. Data control is to capture errors in input data 6. Data validation is done by a (computer) program 7. A check digit is used in the invoice number of an invoice (in this example only) 8. Searching is more efficient if the data are sorted 9. The following is a valid data using even parity check 010100011 10. The following is correct Merging gives a sorted list from two sorted lists 11. How many bytes are there in 32 bits? (1 byte = 8 bits) 4 bytes 12. How many bytes are used to represent 7 Chinese characters? (1 Chinese Character requires 2 bytes, why?) 14 bytes 13. A display card uses 16 bits to represent colours. How many different colours can be displayed? 65536 = 216 14. A company sells 200 different items of goods. If a unique binary code is assigned to each item, how many bits are needed for each code? 8 bit=2^8=256 15. What is the binary equivalent of 127(16)? 100100111 16. What is the hexadecimal equivalent of 1011011101(2)? 2DD 17. What is the decimal equivalent of 10110(2)? 16 + 4 + 2 = 22 18. The following requires real-time processing Airline ticket reservation 19. The following is/are characteristics of batch processing The time for developing a system is short The system is relatively simple 20. The following is/are characteristics of real-time processing The hardware should be fast enough

Data and Information P.2 of 4 Part B: Conventional Questions: 21. Arrange the following in ascending order of structure of data: Table, record, character, database, field character, field, record, table, database 22. A data entry clerk incorrectly enters “sharp” for “shark”. a. What kind of error is committed by the clerk? Transcription error b. How can this error be detected? Verification 23. Which of the followings belong(s) to manual input? a. Voice input b. OCR reader c. Chinese character input using Chang-Jei d. Mouse click e. Bar code scanner a,c,d 24. A primary key may or may not be a single field. The following fields are used in the ticketing office of a theatre: Title of movie, date, time, seat number, price What is the combination of the above fields that could form a primary key for ticket records? Date + time + seat number+ (title) 25. Suggest a validation rule for detecting the errors in the following examples: Field Mistyped text a. Name of a person P010 Chan b. Date of birth(dd/mm/yyyy) 12/20/1987 c. Price of a sketch book 2305 d. Code 093773 (original is 097373) e. Grade in conduct Q f. District [missing] a. data type check b. range check for month c. range check d. check digit e. range check f. completeness check (presence check) 26. Rewrite each of the following codes by appending a check digit that is calculated using weighted modulo-11. a. 234

234(8)

b. 174

174(0)

c. 10201 10201(6)

Data and Information P.3 of 4 d. 2256 2256(A) 27. Determine whether the following codes, each with a weighted modulo-11check digit, are valid or not. a. 532(0)

valid (5*4 + 3*3 + 2*2 + 0*1 = 33)

b. 10101(A)

valid (1*6 + 0*5 + 1*4 + 0*3 + 1*2 + 10*1 = 22)

c. 631(2)

invalid (6*4 + 3*3 + 1*2 + 2 *1 = 37)

d. 752(8)

valid (7*4 + 5 * 3 + 2*2 + 8*1 = 55)

28. A binary search is to be carried out from 80,000 records. How many records will remain to be searched from if the search is still not successful after the 5th comparison? 2500

(8000040000200001000050002500)

29. A word document consists of 5246 words. The cursor position is located just after the 3528th word. Determine the largest number of comparison needed to make to search for a keyword if the search direction is a. forward 1718

(=5246 –3528)

b. backward 3528 30. Arrange the following alphanumeric data in ascending order: a) Cheung, Chung, Chang, Chan, Chen Chan, Chang, Chen, Cheung, Chung b) CAB, BCA, BcA, aCB, baC, bcA BCA, BcA, CAB, aCB, baC, bcA c) A84d, G84d, GA56, FfAQ A84d, FfAQ, G84d, GA56, 31. The following data is to be sorted into ascending order using bubble sort. Determine the intermediate results after each pass: 8, 3, 5, 6, 1, 24, 12 ( 3,8,5,6,1,24,12 3,5,8,6,1,24,12 3,5,6,8,1,24,12 3,5,6,1,8,24,12) 3, 5, 6, 1, 8, 12, 24 (1st Pass) 3, 5, 1, 6, 8, 12, 24 (2nd Pass) 3, 1, 5, 6, 8, 12, 24

(3rd Pass)

1, 3, 5, 6, 8, 12, 24 (4th Pass) 1, 3, 5, 6, 8, 12, 24 (5th Pass)

Data and Information P.4 of 4 1, 3, 5, 6, 8, 12, 24 (6 Pass) th

32. The following data have been transmitted over a long cable. The sender has appended a parity bit so that number of 1’s in each byte before transmission are odd 1: 010101110 2: 010010011 3: 001101101 4: 100101100 5: 011011111 a) Which of the above data would be identified as incorrect by the receiver? data (2) and (4) (even parity, but the rule is odd parity) b) For those correctly transmitted, find the characters represented by the binary codes. (1) W (ascii code is 64+16+4+2+1=87) (3) 6 (ascii code is 32+16+4+2= 54) (5) o “small oh” (ascii code is 64+32+8+4+2+1 = 111) c) It is possible that those “correctly transmitted” data may contain errors that are not identified by the receiver. Explain If the first data 010101110 is wrongly transmitted as 011001110, it is still of odd parity, the receiver would treat it as “correctly transmitted”