compiled from last IB Exam Papers

1. A spreadsheet is used to calculate the cost of carpeting a house. It is shown here with the formula view switched on so that you can see how it is constructed (Image is not included)

(a)  Identify the two functions used in this spreadsheet. [2 marks]

SUM

VLOOKUP

(b)  (i) Cell D12 contains the expression (D2:D10). Describe the meaning of the information in this expression. [2 marks]

range

the contents of all the cells

from D2 to D10.

(b)  (ii) Cell D13 contains an absolute and a relative cell reference. Define the term absolute cell reference. [2 marks]

a cell reference that does not change

it prevents changes if the cell is copied

it prevents changes if the contents of the cell are moved

any reference to method used such as dollar sign or named cell.

(c)   Explain how features of a spreadsheet can be used in order to investigate “what-if” questions. [4 marks]

Answers may include:

– use of formulae can establish relationships

– use of variables to hold different data items

– instant recalculation

– a scenario can be modelled

– consequences of actions can be predicted

– goal seeking can be used to determine the variable values needed for a desired result

– example of a suitable scenario described.


2.
One way to make money from a web site is to place advertisements on it. One web search engine company allows the web site owner to add some HTML code to the web site, which searches the site for content and delivers advertisements relevant to that site. When a visitor to the web site clicks on a link to an advertisement, the web site owner earns a small fee. The more visitors there are to the site the more chance the owner will make money from the advertisements displayed on the site. (Image is not included)

(a)  HTTP stands for Hyper Text Transfer Protocol. Define the term protocol in this context. [2 marks]

a set of rules/standards

determines how the data is to be transmitted/transferred

establishes connection with server.

(b) Describe how the search engine determines relevant advertisements to display on this or other web sites. [4 marks]

– uses algorithm(s)

– web site words (content) scanned

– HTML scanned

– meta tags scanned

– words looked up in database

– words used as search keys in database of advertisements

– system for matching with advertisement

– suitable advertisements selected

– advertisements copied into web page.

(c)  Explain two ways in which the number of visitors to this or other web sites can be increased. [4 marks]

Answers may include:

– make sure that relevant key words are used

– create links to other web sites

– use meta tags

– pay search engine provider to improve page ranking

– advertise his own web site/examples of where advertisements might be

– placed ensure that the web site has unique selling points

– build valuable content on to web site to encourage traffic


3.
The Oyster card is an electronic ticket that is used in London to pay for travel on trains run by Transport for London. It contains an RFID (Radio Frequency Identification) system and it can be charged with money. The amount of credit on the card is stored in the RFID chip on the card. Money is deducted each time a journey is made.

When entering an underground station the card is identified by being touched on the card reader so the RFID signal is detected. On leaving the station at the end of the journey the cost of the fare is deducted from the card. People are encouraged to use Oyster cards by making the fares much cheaper when using the card than buying a paper ticket. Also, there is a price “cap” which means that the user will never pay more than a maximum amount each day. If the card balance is too low, access to the trains is denied.

It is possible to register the card online. This allows the user to top it up with money and to view a journey history, like the one below.

Date Time Location Action Balance
23/01/07 15:03 Russell Square Top-up £21.00
15:03 Russell Square Entry
15:17 Oxford Circus Exit £19.50
18:49 Russell Square Entry
19:09 South Kensington Exit £17.00
24/01/07 08:42 Russell Square Entry
08:52 Euston Square Exit £12.40

(a)  The RFID readers have a short range of 0-8 centimetres. Identify two reasons why the range needs to be short. [2 marks]

– to avoid cards being read by accident

– avoid charging passers-by (a consequence).

(b) Identify four possible tasks the Oyster software would need to perform when an Oyster card is used at a station. [4 marks]

– read the number / scans card

– read the amount of money on the card

– check it is valid

– record entry (place/time)

– record exit (place/time)

– record journey details

– access database

– check that there is enough money for a journey on the card

– if OK, open barrier

– deduct money for journey

– monitor daily cap

– add money to card if topped up online

– write new amount back to card.

(c)   Explain one benefit and one drawback of extending the use of the Oyster card nationally. [4 marks]

Drawbacks

different operators may have incompatible computer systems

– different operators may wish to set their own fares/have different pricing policies

–  issues of scale may make changes necessary to the IT systems

– cost of introducing the technology

– worries over privacy/examples of this

– worries over fraud.

Benefits

– easier to plan travel nationally/across UK

– more flexible travel nationally/across UK

– may be able to use technology to pay for other goods/services.

N.B. Answers that relate to the general use of the Oyster card is not accepted.

The question relates to extending its use.

4. An author writes IT text books at home using his PC. He illustrates his work with many screen shots and images obtained from web sites, showing readers how to carry out various actions. He sends the images as bitmapped files. He sends his work to the publisher using his broadband internet connection.

(a)  Define the term bandwidth. [2 marks]

Answers may include:

– difference between highest and lowest frequencies that can be transmitted

– the number of channels / frequencies can be carried simultaneously by a connection

– the rate at which data can be transmitted any mention of units used

– the number of bits that can be transmitted every second.

(b) Describe one advantage and one disadvantage of sending the images as bitmapped files instead of vector graphics files. [4 marks]

Answers may include:

– bitmapped images made from pixels/dots

– each dot is separately

– stored pictures are easily edited

– bitmapped files are large files/vector graphics are small files

– bitmapped files upload slowly/vector graphics files upload quickly

– bitmapped images do not enlarge successfully

– suffer from pixellation/jagged edges

– bitmapped needed because images are not regular

– screen shots are not line drawings

– vector graphics are stored as mathematical relationships and so can be magnified without a loss of quality

– bitmapped files are more likely to be readable/editable (as suitable software is common)

– resolution issues.

(c)  With reference to one benefit and one problem, explain why there may be  advantages and disadvantages for an author when working from home instead of in the publisher’s office. [4 marks]

One benefit to the author is that he/she does not have to travel to work. The author does not have physically to be on the publisher’s premises in order to get the work done. There is an advantage to the author because it saves time (traveling to and from work) and saves money (petrol costs are reduced). Another advantage to the author is that he or she can work at times to suit. The author is not restricted to conventional working hours, e.g. 9.00am to 5.00pm. This is an advantage because the author may have family commitments during the day, e.g. taking children to and from school. Working from home allows more flexible and appropriate use of time. Another advantage could be the environmental benefits of working from home. A disadvantage of working from home is the frequent disruptions that could occur from such things as family members, pets, neighbours and phone calls. This makes it very hard for the author to have a long block of uninterrupted time that may be needed in order to meet deadlines. Another problem of working from home is the delineation between work time and home time. Too often when working from home, work time intrudes into family time/leisure time. This can lead to family problems. Another disadvantage could be the loss of peer/colleague interaction, so important for professional development. The author has to be very disciplined.