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.
(b) Cell D12 contains the expression (D2:D10). Describe the meaning of the information in this expression. [2 marks]
(c) Explain how features of a spreadsheet can be used in order to investigate “what-if” questions.[4 marks]
Answers:
a) -
b) The information ranging from cell D2 to cell D10 (Example SUM=D12:D10, The sum of all number from cell D2 to D10)
c) The "what-if" function can be used in correlation with any feature of a spreadsheet as it merely checks if the set conditions apply to that features outcome or not. Basically a true and false scenario. If a feature was used to calculate the outcome of various cells the "what-if" function can be used to determine whether the outcome of this feature meets certain conditions or not.
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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]
(b) Describe how the search engine determines relevant advertisements to display on this or other web sites. [4 marks]
(c) Explain two ways in which the number of visitors to this or other web sites can be increased.[4 marks]
Answers:
a) Protocol defines the set of rules and guidelines that are followed by the website in order to become one in the first place. Websites can be written in different protocols that offer various functions. In this context Protocol stands for the language that was used to design a language which was Hyper Text.
b) Websites include keywords that define their purpose and use and are commonly also used for search engine optimization. By identifying these key elements the search engine can find matching advertisement and add it to the site.
c)Search engine optimization - The process of adding relevant keywords to your website so that users that are looking for something you are offering by using search engines, your website is more likely to pop up.
Links from other websites - By being the subject or source on other websites people are more likely to end up on your site as they will notice that your information or product is popular and is being referred to by many others. This tec
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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]
(b) Identify four possible tasks the Oyster software would need to perform when an Oyster card is used at a station. [4 marks]
(c) Explain one benefit and one drawback of extending the use of the Oyster card nationally. [4 marks]
Answers:
a) The gates through which people pass though in the London underground are very narrow to increase the amount of people that can go through at the same time. If the range of the readers were to be increased they might pick up the presence of a card accidentally an cause customers to pay by either unwanted means or maybe even more than once.
Another reason is that the information exchange between the card and the reader could be easily eavesdropped as it is not highly secured. The higher the distance the easier it would be to do so.
b) 1. Matching the Serial number of the Oyster card with a database that includes the account information (amount of money on card).
2. Checking if the amount is sufficient for the distance that was traveled by the customer by checking the enter and exit points on another database.
3. Alarming customer if the amount on account is not sufficient for the distance that was traveled by simply not opening the gate.
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