IT

• Data


  Raw numbers, letters, symbols, sounds or images without meaning
• Examples of data


  • P952BR
  • @bbcclick
  • 359
  • 23557.99
• A picture without context is an example of raw data
• The data P952BR could have several meanings, such as a product code, postal/ZIP code, or car registration number, but without context it is meaningless
• Information


  Data that has been processed and given meaning
• Information is data that has been processed and given meaning
• Ways data can be processed to become information

  • Categorising
  • Calculating
  • Summarising
  • Analysing
  • Interpreting
• Information is more useful than raw data because it has meaning and context
• Information can be used to make decisions and take actions
• Data is the raw material that is processed to create information
• Examples of data


  • P952BR
  • @bbcclick
  • 359
  • 23557.99
  • KEY WORD
• Information


  Data with context and meaning
• Examples of data being given context

  • P952BR - A product code

  @bbcclick - A Twitter handle

  359 - Price in Pakistani Rupees
• Examples of data being given context and meaning to become information

  • P952BR - A product code for a can of noodles

  @bbcclick - The Twitter address for the BBC's weekly technology show, Click

  359 - The price of a mobile phone cover
• Direct data source


  Data that is collected for the purpose for which it will be used
• Indirect data source


  Data that was collected for a different purpose (secondary source)
• Direct data is usually used by the person that collected it and for the purpose they collected it
• Indirect data can also be used, for example a journalist basing a news article on existing news articles
• Examples of direct data sources

  • Visiting other shops and noting down prices

  Visiting other shops' websites and noting down prices

  Carrying out a survey of other shop owners to ask their prices
• Examples of indirect data sources

  • Carrying out a survey of customers who have purchased trainers from the other shops

  Looking at till receipts from the shop
• Data collected directly for the purpose for which it is intended is more likely to be accurate and relevant than data obtained from existing data (indirect source)
• Advantages of direct data source

  • The data will be relevant

  The original source is known and can be trusted

  The data is likely to be up to date

  Bias can be eliminated by asking specific questions

  The data can be collected and presented in the format required
• Advantages of indirect data source


  • The data is immediately available

  If statistical analysis is required, then there are more likely to be large samples available
• Accuracy

  Information must be accurate to be considered of good quality
• Examples of inaccurate information


  • Decimal point in the wrong place

  Misspelling

  Misplaced characters
• Relevance


  Information must be relevant to its purpose
• Examples of irrelevant information

  • Being given a bus timetable when you want to catch a train

  Being told the rental price of a car when you want to buy the car

  A user guide for a mobile phone that includes instructions on how to assemble a plug
• Age


  Information must be up to date to be useful
• Examples of out of date information


  • The number of residents in a town based on a census from 2011, but 500 new homes have been built since then

  A rugby score that has not been updated for 5 minutes
• Level of detail


  There needs to be the right amount of information for it to be good quality
• Examples of too little or too much information

  • A pizza order with missing details

  A train timetable that includes all stations between the departure and arrival points
• Completeness


  All information that is required must be provided
• y forgot to say what type of base they wanted and where it should be delivered to. The pizza company does not have enough information to fulfil the order
• Completeness


  All information that is required must be provided in order for it to be of good quality. Not having all the information required means it cannot be used properly
• Accuracy, relevance, level of detail and completeness affect the quality of information
• Encryption


  Scrambling data so it cannot be understood without a decryption key to make it unreadable if intercepted
• Cipher


  A secret way of writing, a code used to convert a message into an encrypted message
• Caesar cipher


  A shift cipher that selects replacement letters by shifting along the alphabet
• Encrypting with Caesar cipher


  1. Original letter

  2. Shift by 3 letters

  3. Encrypted letter
• Symmetric encryption


  Requires both sender and recipient to possess a secret encryption and decryption key (private key)